Based on the length of this question, would it be a good strategy to look at the conclusion of each answer choice to determine the correct answer? I took this approach, got the right answer, and got through it relatively quickly. Just wasn't sure if the structure of these types of questions are always the same.

My brain gave up after a few minutes, but this is what I was able to salvage from it.

"disciplines (of smart people) are usually part of a disciplines of meaning vs. writing"

Can you elaborate on why (A) can't be the answer?

I was between (A) and (D) but still isn't convinced that (A) does not undermine the argument, if true. Both sounds like they are getting to the same point. (D) acquired confirmation whereas (A) original beliefs are correct....

stop making so much sense

I would agree with msdaisy, "which makes it easy to acquire blah blah blah" is a necessary/sufficient statement, where as, the answer D, stipulates that "it is" part of learning geometry. I think this language is a bit strong, and we don't have sufficient proof to make that claim. Thus, should not be an incorrect answer.

This explanation is really helpful. But, I'm still struggling to understand how "change" can be use interchangeably with "undermine". Can someone shed some light on this?