Question

that man is a doctor____ and works at the clinic.
,
:
nothing needed

Explanation:

The sentence has two parallel predicates ("is a doctor" and "works at the clinic") that share the subject "That man". No punctuation is needed between them because they are simple compound predicates connected by "and" without an independent clause following. Adding a comma or colon would create an unnecessary pause or incorrect structure.

Answer:

nothing needed