14. (B)
Question type: Weaken the Conclusion
The conclusion of this argument is that cavemen stood up before they developed sophisticated tools. Why? Because making those tools requires free use of your hands, and standing upright makes this possible.
Seems like a good argument, but let's think how we might debate it. Couldn't those cavemen have gotten their hands free some other way? Maybe while sitting?
A-ha! Standing upright is a sufficient condition for having free use of your hands, but it's not necessary. The argument is having you think that it goes Soph. Tools --> Free hands --> Standing upright.
But, it's just: Soph. Tools --> Free hands & Standing upright --> Free hands
So, with that in mind, let's look at the answers:
(A) Animals? Out of scope! And, who's talking about basic tools? We're talking about the fancy stuff!
(B) looks good - it's an example of people that didn't stand upright having tools. It emphasizes that standing upright is not necessary. With (B) in place, what does tool use have to do with standing?
It might have given you pause that this answer doesn't say that these stooped cave people developed the tools themselves. Indeed, we have to assume that the fact that the tools belonged to these people means they developed them - but that is a small assumption, especially since the assumptions you'd have to make in the other direction are pretty large (i.e. that these stoopers somehow got their hands on tools made by upright cave people who were around at the same time).
(C) is not helpful. First of all how many is "many"? And, so what if a bunch of upright-standing cavemen didn't have sophisticated tools? Maybe they were not the smartest of cavemen. Maybe others still did.
(D) is shifting the discussion to dexterity. The argument is focused on whether these cavemen has free use of their hands. For all we know, the cavemen who didn't have free use of their hands were very dexterous, but because of that dang limited use of their hands, they couldn't make those fancy tools.
(E) is similar to (D) in that it's shifting the conversation to the use of tools. We're interested in who could develop tools.
edited for clarity!