Chaffee Corporation Staffs a Helpline to Answer Questions from Customers

Multiple Choice

Chaffee Corporation staffs a helpline to answer questions from customers. The costs of operating the helpline are variable with respect to the number of calls in a month. At a volume of 33,000 calls in a month, the costs of operating the helpline total $742,500.
-To the nearest whole cent,what should be the average cost of operating the helpline per call at a volume of 36,100 calls in a month? (Assume that this call volume is within the relevant range. )

A) $21.54
B) $20.57
C) $21.34
D) $22.50