A company purchased 90 units for $30 each on 31 January It purchased 200 units for $25 each on 28 February It sold 200 units for $60 each from 1 March to 31 December. If the company uses the weighted - average inventory costing method, calculate the amount of cost of sales on the income statement for the year ending 31 December (Assume the company uses the perpetual inventory system) O A. $2 700 OB. S5 000 C. S5 310 OD. $7 700