Happy to help. This is a parallel method of reasoning question. In the stimulus, the author uses an analogy to cast doubt on the reasoning of the higher apes' ability for language. Basically, the argument is casting doubt on the speculation that apes have an advanced ability, but they simply never use it. In the answer choices, we want an answer that uses an analogy to cast doubt on the claim it's trying to attack.
(C) says, "Arguing that the human brain has telekinetic powers that no humans have ever exercised is rather like arguing that some insect has legs but never uses them to walk."
(C) is just what we're looking for, and it matches our anticipation well. (C) contains two examples of higher abilities/functions not being put to use, with one of the examples being used to cast doubt on the other one. This closely mimics the structure of the argument in the stimulus, so it's the correct answer choice.
Does this make sense? Let us know if you have any other questions!
