Haley Wants to Stop Eating So Many Sweets

Haley wants to stop eating so many sweets. What do we know about strengthening one's self-control that can help her accomplish her goal?

A) Self-control is like a muscle that needs to be exercised incrementally over time for the best results, so Haley should consider practicing her self-control in another area first.
B) Self-control is an all-or-nothing concept, so Haley should simply stop eating sweets if that's her goal.
C) Self-control is an illusion; the only real way for Haley to reach her goal is to completely change her environment to avoid sweets altogether.
D) Self-control is completely determined by situation so sometimes people have it and sometimes they don't, making it very difficult for Haley to achieve her goal.