Gross profit is correctly ascertained by

Gross profit is the profit earned by a business before accounting for operating expenses such as rent, salaries, and taxes. To calculate gross profit, we need to subtract the cost of goods sold (COGS) from the total sales revenue. COGS is the cost incurred by a business to acquire or produce the goods sold. Therefore, the correct option to calculate gross profit is to subtract the cost of goods sold from sales. The other options mentioned are not accurate methods to calculate gross profit. Adding opening stock to purchases or adding closing stock to sales does not account for the actual cost of goods sold during the accounting period. Subtracting returns outwards from purchases or subtracting returns inwards from sales only accounts for the returns and not the total cost of goods sold.