Mary Paid $456 for an Annual Contract to an ISP

Multiple Choice

Mary paid $456 for an annual contract to an ISP on July 1, 2012. She terminated her contract with the ISP on March 8. The contract requires to refund a prorated amount to the exact number of days remaining in the period of coverage. A $50 service charge is then deducted. What refund will Mary receive?

A) $142.42
B) $92.42
C) $54.94
D) $50
E) $0