Answer:
C
Step-by-step explanation:
A: Word choice usually is one of the last things you do when you're writing an essay, so this answer is wrong right off the bat.
B: Conventions are things such as spelling, grammer, puncuation, etc. Again, this is one of the last things you would do.
C: This answer makes the most sense because John is still brainstorming, and doesnt know where to begin. Formulating ideas is the first part of writing a paper.
D: Voice is similar to conventions. While it is important for a narrative, you cant work on the "voice" you're trying to convey without having an essay.