The correct answer is D. Rs. 100 (Profit).
Gross profit is the difference between the revenue generated from selling goods or services and the cost of goods sold. It is calculated by subtracting the cost of goods sold from the sales revenue.
In this case, the cost of goods sold is Rs. 7,900, the sales revenue is Rs. 11,000, and the purchase is Rs. 3,000. Therefore, the gross profit is Rs. 11,000 – Rs. 7,900 = Rs. 3,100.
However, the purchase is not part of the cost of goods sold. The cost of goods sold is only the cost of the goods that were sold. In this case, the cost of the goods that were sold is Rs. 7,900. Therefore, the gross profit is Rs. 11,000 – Rs. 7,900 = Rs. 3,100 – Rs. 3,000 = Rs. 100.