Answer:
C. Working to the point of exhaustion at least two times per week
Explanation:
Working out to the point of exhaustion may even discourage someone from their fitness plan. Although I'm not exactly sure what B means, everything else will help someone stick to a fitness plan.
The antecedent in the sentence is C
In this sentence the word <em>sage</em> means wise or sensible, a piece of advice given by someone who knows about the subject.
