Thanks for the question! So we’re asked here for something that the authors would be most likely to disagree over. As long as they disagree over it, it’s the correct answer choice, regardless of how small a point it is.
So now let’s take a look at (C), which tells us that the authors would be most likely to disagree over whether human language and animal communication differ from one another qualitatively or merely in a matter of degree. In other words, are they basically the same thing, just at different levels (like water and ice cubes), or are they completely two different things?
What would passage A say about answer choice (C)? Well, we know that passage A is all about emphasizing the differences between human speech and animal speech. For example, animal vocalizations’ communication is “inadvertent” because most animals (except maybe chimpanzees) can’t attribute mental states to others (lines 6-11). So the author is drawing what seem to be categorical distinctions between human speech and animal speech. So passage A would probably say that human language and animal communication differ from one another qualitatively; they’re two different things. It’s not like animal language is just dumbed down human language.
What would passage B say about answer choice (C)? Well, passage B is basically questioning the things that passage A are saying, and saying that this distinction between animal speech and human speech is too strong to make. And passage B talks about how “the assumption that the difference between animal and human communication is qualitative rather than merely quantitative” is called into question in lines 56-62. In other words, passage B would disagree that the difference is qualitative, passage B thinks that it’s quantitative, or a matter of degree! So the two passages disagree on (C), which makes it the correct answer.
Hope this helps! Feel free to ask any other questions that you might have.
