Which One of the Following Mathematical Definitions Is Correct

Which one of the following mathematical definitions is correct?

A) The cost of switching credit policies is defined as the quantity multiplied by (P-v) .
B) The net present value of extending credit is equal to -v + (P- v) /R.
C) The total cost of holding inventory is equal to (Q) (CC) + (F) (T/Q) .
D) The economic order quantity is equal to the square root of (T) (F) /CC.
E) Accounts receivable is defined as average daily sales multiplied by the average collection period.