Swinnerton Clothing Company's balance sheet showed total current assets as indicated below, all of which were required in operations. Its current liabilities consisted of $575 of accounts payable, $300 of 6% short-term notes payable to the bank, and $145 of accrued wages and taxes. What was its net operating working capital that was financed by investors?

a. 2.63

b. 4.59

c. 3.63

d. 4.17