Concept:Gross profit is the difference between sales and the cost of goods sold.Explanation:First, calculate the cost of goods sold:Cost of goods sold = Opening stock + Purchases − Closing stock=10,000+100,000−20,000=Le 90,000Then, compute gross profit:Gross profit = Sales − Cost of goods sold=120,000−90,000=Le 30,000 profit.Answer:A. Le 30,000 profit