B makes sense to me as an alternative hypothesis now... But I still am failing to see how A isn't also a valid alternate hypothesis.

If sticklebacks without armor are able to swim faster, then the argument that "Having a larger size is a better defense against the lake sticklebacks predators" could be wrong, instead having greater speed could be a better defense than having armor..

Am I missing something here y'all? I just can't figure this one out.

This was one was killer for me, I originally thought C but chose D because I made the (perhaps unreasonable) assumption that Rivier's take that the internal compulsions are a result of the force of deities implies that they are not morally responsible for their actions. In my mind, this points to a strong disagreement with Leskie's view that characters are still morally responsible for their own desires, despite the strong role played by the gods as well.

I see now how C is a stronger choice, but wow RC is tough.

I'm still stuck on answer choice C on this one. If live modeling was common in the period, then the fact that "Leo" appeared in the painting is MORE LIKELY to be explained by a factor other than him doing the painting himself THAN it otherwise would be if that piece of information was not included and thus the argument is weakened.

I understand that I am wrong, but I am really having trouble seeing whatever it is that I am missing.