Motor Parts, a Large Auto Parts Store, Did an Experiment

Motor Parts, a large auto parts store, did an experiment to see whether it was faster to have one person work on each car repair or have a team of people work together on a repair. It found that each employee, working independently, could do three to five auto repairs per day. However, when one person removed the old part, another person prepared the new part, and a third person installed the new part, they were able to complete up to twenty repairs per day. This scenario demonstrates that

A) specialization doesn't dramatically increase the output.
B) working independently is more rewarding than working together.
C) specialization requires a company to have fewer skilled workers.
D) people can perform more efficiently if they master just one task rather than all tasks.
E) people should master all tasks even if they will only perform one task.