Accounts payable $30,000
Accounts receiveable $65,000
Accrued liabilities 7,000
Cash 20,000
Intangible assets 40,000
Inventory 72,000
Long-term investments 100,000
Long-term liabilities 75,000
Marketable securities 36,000
Notes payable (short-term) 20,000
Property, plant and equipment 625,000
Prepaid expenses 2,000

Based on the data above, what is the amount of working capital?
a. $238,000
b. 138,000
c. 178,000
d. 64,000