When you are reviewing the conventions in an essay, what are you looking for?
spelling, grammar, and usage
transitions and organization
unnecessary sentences
wording and variety of language

Improper grammar is one of the easiest ways to get a bad grade on any writing project. So based on the options available, I'd say A. Spelling, grammar, and usage is the best answer.

answer; the parasympathetic nervous system;

answer; exaggerate what you believe is the deception and state it, hoping that the other will jump in to "correct" the statement;