Which of the Following Is a Reason Why Using Placebos

Which of the following is a reason why using placebos in experiments that test the effectiveness of psychotherapy is more complicated than in experiments that test the effectiveness of drug therapies?

A) The therapists know if they are providing the treatment or control therapy.
B) The effectiveness of psychotherapy is less than that of drug therapy, so the difference is harder to measure accurately.
C) The placebo treatment often involves specific factors, which increase effectiveness.
D) There are serious ethical concerns about withholding psychotherapy from patients.