A company purchased 130 units for $30 each on 31 January. It purchased 200 units for $35 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.) Select one: a. $6606 O b. $3900 O c. $10.900 O d. $7000