BullsNBears, a Purveyor of Financial Databases, Estimates It They Disburses

BullsNBears, a purveyor of financial databases, estimates it they disburses $440,000 monthly in order to pay bills. The firm's opportunity rate is 5%. The fixed cost of transferring money is $25 per transfer. Based on historical data, the standard deviation of monthly cash flows is $15,000 and the lower cash balance limit is $20,000. For Miller-Orr model questions, assume the interest rate is 0.5% per month.

Using the Miller-Orr model, what is the optimum upper limit?

A) $26,182
B) $39,449
C) $48,347
D) $52,150
E) $79,617