The Text Authors Punctuate the Closing of Their Book with the Exclamation

The text authors punctuate the closing of their book with the exclamation that "Psychotherapy works!" What they mean is that:

A) psychotherapy is effective for some people with particular kinds of problems.
B) psychotherapy is effective in the vast majority of cases,but not as effective as biomedical interventions.
C) psychotherapy yields large effect sizes that rival or exceed those in biomedicine.
D) cognitive-behavioral and interpersonal psychotherapies are effective while other therapies are less so.