Inhabitants refers to people or animals that live in large areas or to people or animals that are adapted to particular physical environments.
Occupants refers to people who live in a particular place, and it implies that these people are holding possession of the place.
Doctors, a general term, refers to all who have qualified in medicine.
Physicians refers to doctors in general practice--often those who have taken a higher medical degree.
Candidates refers to people who seek or are nominated for a certain position.
Applicants refers, most strongly, to people who are formally requesting a certain position.
I hope this helps.
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