An Art Therapist Wants to Determine Whether Art Therapy Helps

An art therapist wants to determine whether art therapy helps reduce confusion among clients who are diagnosed with Alzheimer's disease. What treatment-design strategy would be best for her outcomes study?

A) Treatment intensity, in order to measure the effects of early or longer art therapy intervention
B) Treatment versus no treatment, in order to measure the overall quality of the art therapy program
C) Treatment provider comparison, in order to prove that training makes a difference in delivering effective treatment
D) Treatment "a" versus treatment "b," in order to prove that cognitive-behavioral therapy doesn't work with Alzheimer's clients