Final answer:
Working capital is the difference between current assets and current liabilities. The working capital in this case is $58,000.
Step-by-step explanation:
Working capital is the difference between a company's current assets and current liabilities. To calculate it, subtract the current liabilities from the current assets. In this case, the current assets are $100,000 and the current liabilities are $42,000. So, the working capital is $100,000 - $42,000 = $58,000. Therefore, the correct answer is a. $58,000.