A doctor is a very important person. He works very hard. The doctor gives medicine to sick people. He wears a white coat. A stethoscope hangs around the doctor's neck. He uses it to listen to the heartbeat of the sick people. The doctor works in clinics and hospitals. His job is very difficult. A doctor is a/an:

• A.  important person.      
• B.  useless person.
• C.  big and huge person.    
• D.  great person.
• E.  None of these