revised Net profit

Hello John, Could you help me to choose the correct answer, please? The accountant at Investotech discovered the following errors after calculating the company’s profit for 20X3: (a) A non-current asset costing $50,000 has been included in the purchases account (b) Stationery costing $10,000 has been included as closing inventory of raw materials, instead of stationery expenses What is the effect of these errors on gross profit and net profit? A Understatement of gross profit by $40,000 and understatement of net profit by $30,000 B Understatement of both gross profit and net profit by $40,000 C Understatement of gross profit by $60,000 and understatement of net profit by $50,000 D Overstatement of both gross profit and net profit by $60,000 in the BPP book the answer which is given is B. I agree that gross profit would be understated by 40000 but what about the net profit shouldn't it be the same as gross profit. Since we included the error in closing inventory, we cannot include it once more in expense unless we correct it. However, the question asks the effect of errors on Profit?.