The correct answer is: C. total assets.

Total capital employed is the total amount of money that a company has invested in its assets. It is calculated by adding together the company's fixed assets and its net working capital.

Fixed assets are the assets that a company owns and uses in its day-to-day operations, such as land, buildings, and equipment. Net working capital is the difference between a company's current assets and its current liabilities. Current assets are the assets that a company expects to convert into cash within one year, such as cash, accounts receivable, and inventory. Current liabilities are the liabilities that a company expects to pay within one year, such as accounts payable and short-term debt.

Total capital employed is an important measure of a company's financial health. It indicates how much money a company has invested in its business and how much it has available to finance its operations. A high level of total capital employed can indicate that a company is well-funded and has a strong financial position. However, a high level of total capital employed can also indicate that a company is overleveraged and has too much debt.

The other options are incorrect because they do not include all of the assets that a company owns. Option A, fixed assets, only includes the company's fixed assets. Option B, fixed assets + net working capital, includes the company's fixed assets and its net working capital. However, it does not include the company's current assets or its current liabilities. Option D, net worth, is the difference between a company's assets and its liabilities. It does not include the company's current assets or its current liabilities.