I was torn between C and D after eliminating the other choices, and I ended up thinking C was a trick answer and incorrectly choosing D instead. This was my reasoning:

People need more than haircuts and consultants. If a nation develops a service economy and deemphasizes manufacturing, it still needs manufactured goods. (Bad assumption?) This need for manufactured goods would exist even if the nation's markets for services were primarily local. One way to get the manufactured goods would be to import them, which would constitute international trade. But, the stem says that the decrease in manufacturing has led to less international trade. So I want a reason for this nation's surprising self-sufficiency. Somehow, everyone is a hairdresser or a consultant or some other kind of service professional, and yet the nation has the manufactured goods it needs. Choice D gives me a reason: the nation has automated its manufacturing. This could explain why a smaller proportion of the workforce is employed in manufacturing and yet the nation's reliance on other nations (for manufactured goods) has not increased.

I think I looked at this question too hard. But anyway, is there a way I could quickly disqualify D?

Is it still a concession if the author then attempts to argue against that specific point? What if the author had followed with "but not all popular movies are good movies?"

I felt like #1 could have been an argument, albeit a very weak one. When I asked myself why I should believe the conclusion that some mammals show growth rings on their teeth in the form of seasonal cementum bands, it seemed supported by the premise that they found bands of consistent width on the teeth of excavated stone age pigs.

The matters of the width and the outer layer seem unrelated and/or liable to undermine the conclusion, and cementum and seasonality aren’t addressed. So I can understand why it’d be a poor argument, but I’m having trouble understanding why we’d say it’s not an argument at all.

In these cases where I perceive a particularly weak or spurious argument like this (e.g., missing key premises and/or including non-sequitors), is it a safer bet to simply assume that no argument is being made at all?

#1 raised a big question for me: Can established sufficiency relationships be flipped into necessity relationships? Or can I only derive a contrapositive statement?

Per the indicator word, Not Seeing Arun (xSA) is a sufficient condition of Arun being in the Next Room (ANR).

In the contrapositive, Seeing Arun (SA) means there's No Arun in the Next Room (xANR).

I'd express all this as the stacking circles where xSA is a subset of ANR. Or SA is a subset of xANR.

Following the necessity relationship I derived from these circles in previous circles, it would stand to reason that ANR is a necessary condition of xSA. In other words, Arun being in the Next Room is necessary for me to Not See Arun.

This ultimately doesn't make sense. Arun could be on the other side of the planet, and I wouldn't see him. So it's not necessary for him to simply be in the next room.

I thought maybe this could be resolved with a Truth/Validity distinction. The statement "it is necessary for Arun to be in the Next Room for me to Not See Arun" is valid but based on an untrue premise.

But that also doesn't work. The statement "I would not be able to see Arun if he were in the next room" isn't fundamentally untrue in any way.

What am I missing here?