According to the Article on Weight Reduction by Axsom and Cooper

According to the article on weight reduction by Axsom and Cooper, the factor that underlies the effectiveness of virtually all forms of psychotherapy is:

A) changing a negative self-concept to a positive self-concept.
B) expending effort to participate in the therapy.
C) learning logical, rational decision-making procedures.
D) learning to accept oneself for the person one is.