Answer:
A, I believe
Explanation:
When reading a draft you need to take into what you need in your final draft and what you don't need. Although concentrating on one feature sounds good at first, it could be extremely time consuming, and honestly isn't the best way to go. Meanwhile A pretty much does that but at a faster pace, as well as you know what you do and don't need in the end.
TL;DR:
In all, it's just much easier to do a than b when actually doing a reread of a draft, so a :)
