The Reason So Many Assessments Have Little Impact on Psychological

The reason so many assessments have little impact on psychological services is:

A) The validity of a test is conditional on the purpose for which it is being used and the population with which it is used
B) most of these instruments were originally designed for assessment, not intervention
C) instruments useful for evaluating personality characteristics or psychosocial functioning are not necessarily valid for determining optimal ways to enhance these areas
D) all of the above