Looks like choice C would be something that would make things more stressful for the procrastinator. Just inferring from what I can see from the answer explanation, I guess it's expected you realize that anxiety is an underlying factor for procrastination. Only choices A offers a reasonable a solution that would reduce stress.
I can totally see why you'd choose C though based on how the passage talks about doing something similar to C on subjects they are studying. IMO, I feel like the quality of this question is a kinda poor, a bit too convoluted compared to EK, AAMC, and NS questions I've been doing.