SAT Evidence Questions

For questions in the reading section that ask you to find the evidence proving your answer to the previous question, will all the proof ALWAYS be within the lines given in the answer choice, or will there be cases where the surrounding context, rather than the lines itself, will directly prove it? For example #50 on CB practice test #5, obviously you can eliminate all other answer choices except A but the direct proof is in the previous paragraph, not within those lines. I mess up on these evidence questions a lot because I either don’t think any of them prove the point (and consequently end up guessing and getting it wrong) or I’m stuck between 2 answer choices that both seem to prove the point (I try to figure out which one proves it better but sometimes i just guess).