Final answer:
A psychiatrist can prescribe medication and use biomedical treatments, whereas a clinical psychologist cannot prescribe medication but can conduct psychological assessments. The correct option is A.
Step-by-step explanation:
The major difference between a clinical psychologist and a psychiatrist is that a psychiatrist can use biomedical treatment.
Psychiatrists have a doctor of medicine degree (MD) and can prescribe medications, while clinical psychologists, who have either a PhD or a PsyD, do not prescribe medication but can administer and interpret psychological tests. Both professionals can conduct therapy and counseling, and work in a variety of settings including private practice and hospitals.