The disorder where one is fearful of public spaces and leaving the comfort of one’s own home is
a. acrophobia
b. coulrophobia
c. claustrophobia
d. agoraphobia

The correct answer is: Agoraphobia.

Agoraphobia includes all unknown situations, when the person perceives themselves not to be safe or to be in some way uncomfortable. 

The word comes from the Greek word "Agora" (one example of an Agora is the famous ancient Agora of Athens) meaning public space and Phobia, meaning fear.

d. agoraphobia

A clinical psychologist 1) assesses a patient, 2) diagnose the patients' disorders and, 3) recommend possible treatment.

Possible treatments are undergoing family therapy, group therapy, behavioral therapy, and hypnotherapy. However, when there is a need to prescribe medication to treat a disorder, the patient is referred to another mental health professional, who can prescribe medication.