"credentials" in the last paragraph refers to______.

A．They are not competent in their treatment of schoolchildren because they haven't received proper training.
B．They have no proper credentials to justify their work in psychopharmacology.
C．Their involvement in psychopharmacology sometimes should be limited, as they are not as well trained and experienced as clinical psychologists do.
D．They should get a Psy. Degree before they are involved ii1 the psychological treatment of schoolchildren.

A．prescribing the medication needs the identified criteria
B．the absence of the practitioners is a serious obstacle
C．the presence of more practitioners is a new problem
D．identifying the practitioner is of great importance