Gre doubt in 1bTC

The idea of a “language instinct” may seem _____ to those who think of language as the zenith of the human intellect and of instincts as brute impulses.
A. jarring
B. plausible
C. gratifying
D. inevitable
E. conciliatory

Can someone explain how to solve this? I got this wrong when I tried to solve this with connotation and semantic guess.
Answer is A btw, but I don’t understand how!?

can you give me the main idea of the second half of the sentence?

those who think of language as the zenith of the human intellect and of instincts as brute impulses - talks about the duality of how people consider language as epitome of intellect and also similarly how instincts are inner impulses. I could not fully make a lot of the idea to be honest, which is way I got confused and how do I exactly approach a question like this whose meaning seems tough to me in exam without panicking ?

Just embrace the panic. Ha ha ha! I am kidding!

If you don’t understand the meaning of a clause that you clearly need to use, guess and skip and come back at the very end if you have time.

But you did a good job here paraphrasing the clause/idea!