Plano Company's balance sheet showed operating current assets of $3,000. Its current liabilities consisted of $600 of accounts payable, $500 of 5% short-term notes payable to the bank, and $400 of accrued wages and taxes. What was its net operating working capital?
a. $1,500
b. $1,650
c. $1,800
d. $2,000
e. $2,500