Leas 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 25,000 calls in a month, the costs of operating the helpline total $452,500.
To the nearest whole dollar, what should be the total cost of operating the helpline costs at a volume of 23,900 calls in a month? (Assume that this call volume is within the relevant range.)

a. $442,545
b. $452,500
c. $473,326
d. $432,590