Answer:
C - Tell his boss that the coworker is slacking off
Step-by-step explanation:
A - If Dylann complains to his other members they can't do anything about it so it would be useless
B - If he were to ask the co-worker about his jobs responsibilities, the co-worker might not care, in some cases this could work.
C - He could tell his boss who could have the co-worker fired, since hes not helping and still getting paid
D - He shouldn't complete his co-workers for him, or else this would encourage the co-worker to not want to work