Why should an IT project manager use most likely, optimistic, and pessimistic scenarios when calculating the time required for a task?

A. Some staff members will take longer than other staff members to do the same type of work.

B. Each staff member will have a dollar amount assigned to the work hour. The optimistic and pessimistic scenarios can predict which staff member is the most valuable.

C. The most likely, optimistic, and pessimistic scenarios allow an IT project manager to predict the average time expense required to complete a task.

D. The most likely, optimistic, and pessimistic scenarios allow an IT project manager to predict the average amount of labor required to complete a task.