The question stem says the reasoning above is flawed in that it blanks.

So this is a flaw question. Let's go ahead and break down this argument and then figure out why

the premises don't prove the conclusion. We're told that Roberta is irritable only when she is

That's a conditional indicator that suggests the reasoning in this argument is going to be based on

conditional logic. So I'm going to go ahead and diagram those two statements just for the purpose

of this explanation to help you see what's going on in the argument. Only when introduces a

necessary condition. So the first sentence here, the first part of the first sentence means if

Roberta is irritable, then she must be tired. Being tired is a necessary condition in order

for her to be irritable. And similarly, being tired is also a necessary condition in order for

her to be losing things. So if she loses things, that guarantees that she must be tired. Now one

thing we would want to register after reading the first sentence is that Roberta being tired

would not necessarily prove that she's irritable and it would not necessarily prove that she loses

things. Right now, all we know is that there are these two conditions here, either one of which

would lead to her being tired or rather guarantee that she is tired. But that doesn't mean if she's

tired, she must be irritable or if she's tired, she must be losing something. The next premise

says she has been yawning all day. And does yawning all day mean that she's tired? Not necessarily.

So I don't want to treat that claim that she's been yawning as the statement that she has been

tired. Right now, there's no clear impact from the fact that she's yawning. But I do see that there's

another component of the premise. So since she has been yawning all day and has just lost her keys,

and then the conclusion says she is almost certainly irritable. So this is the conclusion.

The first sentence here, which gave us these conditionals, is a premise. And then we have

another premise, which is that she has lost her keys. Now, technically, you could also think of

yawning all day as a premise. But I'm paying less attention to that because it doesn't directly

interact with our conditionals. Whereas we do have a statement about her losing something.

And that interacts with at least this conditional down here about losing something. We know that she

has lost her keys. And so that's an example of something that would trigger this sufficient

condition here. We know that she has lost something. And that would allow us to conclude

that she is tired. Now, so far, I've just represented what the premises are telling us.

We have these two conditionals, and we know that she has lost something. Now, as I mentioned,

the fact that she has lost her keys would trigger this conditional and allow us to conclude that

she must be tired. So that is an inference we can draw from those two premises. And I'll put that

inference below this dotted line here. This is something that must be true about Roberta,

given what we know from the premises. But do you notice that the conclusion of the argument

is not that Roberta must be tired? Instead, it says Roberta must certainly be irritable.

So at this point, we should have the question, well, how does the author get from these premises,

which could validly reach the inference that she's tired, how does the author get from this

to then reach this flawed conclusion that she must be irritable? This is something that is not

fairly supported by the evidence that we have. And what's happening here is just an example of

the oldest trick in the book. The author is confusing sufficient and necessary conditions,

not of this premise over here, which we can validly use to conclude that because she's lost

her keys, she must be tired. The author's not confusing that part of the argument. What the

author is confusing is this first premise here, that if irritable, that guarantees she's tired.

In the author's mind, this is reversed. The author thinks this means that if she's tired,

then she must be irritable. And because this interpretation is what the author has in mind,

the fact that Roberta has lost something, which would prove that she's tired, and remember,

that's the inference that I drew down here. So the fact she's lost something does prove that

she's tired. The author is taking that idea and thinking that that triggers this sufficient

condition, tired, which then leads the author to think that because she's tired, she must be

irritable. That's how the author gets to this flawed conclusion. But all of this is based on

the flawed interpretation of that first sentence. This is a mistaken interpretation where the author

is confusing what is necessary, tired is necessary, but thinking that that means tired

is sufficient. So when we go to these answers here and we're looking for a description of the flaw,

we know we're looking for something like the author mistakes a necessary condition for irritability as

a sufficient condition. Or the answer could say the author overlooks that someone can be tired

without being irritable. There's a whole bunch of ways that you might describe this mistaken

interpretation. Let's start with answer choice A, which says that the argument infers from a

asserts that tiredness causes yawning. What the author says is that she has been yawning. And

then we also know that because she's lost something, that that would prove that Roberta's tired. But

the author never asserts that her tiredness is causing her yawning. So A is just descriptively

Now, this is an example of circular reasoning, but that's not what's occurring in this argument.

This argument is committing the flaw of confusing sufficient and necessary conditions. It's

misinterpreting a conditional statement. In order to pick answer choice B, you would need to be

convinced that this conclusion was repeated in the premises. But that doesn't happen here. The

conclusion is she's certainly irritable, and we don't see a premise that says she is almost

certainly irritable. So you can't pick a circular reasoning answer choice here. Next, answer choice

here. I mean, sure, maybe there's a single instance of her having lost her keys. But according to this

premise here, if she lost something, that does prove that she's tired. The author is not generalizing

from Roberta being tired to other people, nor is the author generalizing from this circumstance and

then saying Roberta's always tired. The only thing that's happening here is the author is taking

the inference that she must be tired and then thinking that, based on the first sentence,

that tired guarantees irritability. But that's just a reversal of this conditional statement

that has nothing to do with making a broader conclusion than is warranted. Next, answer choice

sufficient condition. Now, D might be very attractive because it talks about a mix-up of

necessary and sufficient, but the problem with D is that it's just about the wrong premise.

The author was not confusing this statement here. The author was confusing this statement.

Answer choice D is accusing the argument of thinking that being tired is sufficient for

losing things, but that's not what the author thought. The author accurately interpreted this

premise and was using the fact that she lost something to then conclude, or rather, reach

the inference that she's tired, and then the author is jumping from the fact she's tired

to thinking that that proves irritability. But that jump here is a reversal of the first premise

about irritability. It's not a reversal of the losing things premise. So that's why answer choice

D is wrong. And finally, E says that the argument takes a necessary condition for Roberta's being

at this first premise here, the author mistakes that to mean this over here, that tired is

sufficient for irritability. This misinterpretation is why the author thinks the fact that she lost

something would prove that she's irritable, because the author recognizes that losing

something proves tiredness, but then mistakenly thinks tiredness proves irritability.