An associate in an office or institution

A. Companion

B. Ally

C. Colleague

D. Accomplice

Answer: Option C

Solution(By Examveda Team)

One word substitute is Colleague.

Companion: a person or animal with whom one spends a lot of time or with whom one travels.
Ally: a state formally cooperating with another for a military or other purpose.
Colleague: a person with whom one works in a profession or business.
Accomplice: a person who helps another commit a crime.