Which ap exam is best to self-study?

Out of AP Bio and AP Env. Science?
The thing is…in my school, we get 5 points added to the class if we take either or. I’ve taken an Honors Bio class…so it would get added to that if I pass and boost my gpa and rank. But it wouldn’t get added to Environmental Science until I take it my senior year (so it won’t affect my college rank, which I want it to). But by graduation I would have moved up a rank maybe (the top 10 students are very close…the slightest gpa points make a difference).
But I have one month to study…so putting that aside, which is the easiest one, or rather, the one that’ll take less time to study?

For Biology, could I just watch Bozeman Science videos and be ready? Or should I try going through Cliffsnotes book? And for Env. Science I heard it should be Princeton Review.