Zumbo Company's balance sheet showed total current assets of $3,500, including a cash balance of $875. This cash balance is excess cash. Its current liabilities consisted of $950 of accounts payable, $775 of 5% short-term notes payable to the bank, and $525 of accrued wages and taxes. What was its net operating working capital?

a. $ 375

b. $ 775

c. $1,150

d. $1,250

e. $2,025