Very clever argument. We're told that we have two groups of patients, 43 to each group. Everyone's got the same illness and receiving the same treatment. The ONLY difference is that one group is the kumbaya group. You know, we want to test the effectiveness (if it exists) of kumbaya so we isolate it. Okay, so... this is exciting what are the results? Well, the next premise tells us that after 200 years, everyone's dead. Therefore (the conclusion says), kumbaya does nothing.
See how ridiculous that argument is? I know I said 200 years whereas the actual premise said 10 years. But, 10 could also be just as ridiculous depending on what assumptions we entertain. How old are the patients? If they're 20 years old, then okay, fine, 10 years is whatever. If they're 100 years old already, then a 10 years later result is ridiculous to report. Of course everyone's dead.
That's precisely the subtly that (C) calls out. (C) says "Look, you should have reported on the results 8 years after, not 10. If you reported 8 years later, then most of the kumbaya group would be alive, while most of the non-kumbaya group would be dead."
(A) is tempting and it certainly doesn't help the argument, but it's a big stretch to say that it hurts the argument. First, we're left with just 4 data points of the original 86. It would be overgeneralizing to say something about the 86 sample from the 4 data points. Second, consider just the data points themselves. All we're told is that the kumbaya 2 lived longer than the non-kumaya 2. Okay, how much longer? 5 years? That'd be nice. Or just 5 seconds? That'd be useless.
Sufficient Assumption question, pretty standard, cookie cutter question that we should be able to anticipate the answer choice.
But, it's difficult because of the embedded argument within an argument, heavy use of referential phrasing, and grammar parsing.
Author's argument begins with "however". The text before "however" is just context/other people's argument that will later serve as the referent for a referential phrase used in the conclusion.
"one must mine the full imp... to make intell prog"
Think about what's necessary and what's sufficient in this relationship. Does mining the full imp guarantee that we'll make intell prog? No. It's the other way around.
"for this, thinkers need intell discipline"
What does "this" refer to?
If you answer both of the above questions correctly, you'll end up with the proper translation of the premise below:
intell prog --> mine full imp --> intell discipline
The conclusion says "this argument for free thought fails". This takes a bit of interpreting. Look at all the text before "however". That's where we get the argument for "free thought". What's the conclusion? Focus on the indicator "because". The conclusion is "free thought is a precondition for intell prog". Now, what's the relationship here? A precondition. Something we must have. A necessary condition.
intell prog --> free thought
That's just the contextual conclusion though. Our author is arguing that that's wrong.
NOT (intell prog --> free thought)
Fully translated, it looks like this:
intell prog --> mine full imp --> intell discipline
_______________
NOT (intell prog --> free thought)
So, how do we make this argument valid? We can make intell discipline imply NO free thought. (C) gives us the contrapositive.
free thought --> NO intell discipline.