Allen Tutors in His Spare Time for Extra Income

Multiple Choice

Allen tutors in his spare time for extra income.Buyers of his service are willing to pay $40 per hour for as many hours Allen is willing to tutor.On a particular day,he is willing to tutor the first hour for $10,the second hour for $18,the third hour for $28,and the fourth hour for $40.Assume Allen is rational in deciding how many hours to tutor.His producer surplus is

A) $40.
B) $64.
C) $12.
D) $56.