Under Your Current Cash Sales Only Policy You Sell 170

Under your current cash sales only policy you sell 170 units a month at a price of $25. Your variable cost per unit is $18 and your monthly interest rate is 2 percent. Based on a recent survey, you believe that you can sell an additional 40 units per month if you offer a net 30 credit policy. What is the net present value of the switch using the one-shot approach?

A) $5,044
B) $6,970
C) $7,584
D) $8,853
E) $9,030