A Good Reason for Developing a System for Classifying and Diagnosing

A good reason for developing a system for classifying and diagnosing psychological disorders is that

A) diagnosis of a disorder aids in finding successful treatments for it.
B) accurate classification of a disorder allows researchers to learn more about the causes of that disorder.
C) it can guide the direction of future research efforts.
D) all of the above
E) none of the above