A. Net working capital is Current Assets – Current Liabilities. Current assets in this case are made up of marketable securities (10,000) + accounts receivable ($60,000) + inventory ($25,000) + supplies ($5,000) for a total of $100,000. Current liabilities are accounts payable ($40,000) + short term debt ($10,000) + accruals ($5,000) for a total of $55,000.  Net working capital = $45,000

B. This answer does not include marketable securities as part of current assets.

C. This answer does not include supplies as part of current assets and it does not include accounts payable as part of current liabilities.

D. This answer does not include accruals as part of current liabilities.