After Much Negotiation with a Customer, a Plumber Agrees to Do

Multiple Choice

After much negotiation with a customer, a plumber agrees to do a job for $50 an hour. In fact, the job is so unpleasant that he would not have done the job for anything less than $50 an hour even though other plumbers have done similar jobs for $40 an hour. Hiswage-related rent is

A) $50
B) $40
C) $100
D) $10
E) $0