The chief reason a person becomes a supervisor is

a. motivation.

b. confidence.

c. work-related knowledge.

d. personality

A supervisor should be in this position because of c. work-related knowledge.: they can correct and better organize the work of the people in their team because of this knowledge.

however, personality and confidence also play a role: a supervisor that is not confident might make people unsure about how to proceed, and if someone is not a natural leader, they might find the work harder and not be as successful as a supervisor. But I think that the best answer is C.