The main difference between a psychologist and a psychiatrist is that a psychiatrist can typically and most psychologists cannot
a.
prescribe medication
b.
diagnose
c.
practice psychotherapy
d.
treat people with varying problems

A:Prescribe medication

Explanation:

Psychiatrist:The psychiatrist trained as medical doctors, they prescribe medication and they spend much more time with their patients on medication management.The psychiatrist's course in which the psychiatrist solve problems of their patients by medication.

Psychologist: The psychologist focus on psychotherapy for  treatment of any patient.The psychologist treatment of  those patients who have mental , emotions and behavioural problems. The psychologist can solve the problems of patient by exercise.The psychologist cannot prescribe medication.

Therefore, the main difference  between a psychologist and a psychiatrist is that a psychiatrist can typically prescribe medication and psychologist cannot.

Hence, Option A , correct.

A:prescribe medication.