* Which of the following best describes the calculation of a business's gross income? * a. Gross income is calculated by adding up all revenue received within a tax year, including returns, allowances, and the cost of goods sold. * b. Gross income is calculated as gross receipts plus returns and allowances, and the cost of goods sold. * c. Gross income equals the sum of rental income, interest and dividends, and the proceeds from the sale of capital assets. * d. Gross income is calculated as gross receipts minus returns and allowances, and the cost of goods sold