Trekking Company markets a climbing kit and uses a perpetual inventory system to account for its merchandise. The beginning balance of the inventory and transactions during January were as follows: January 1 Balance 20 units at $14 January 4 Purchased 30 units at $15 January 23 Sold 35 units at $30 January 30 Purchased 10 units at $16 January 31 Sold 20 units at $30 If the ending inventory is valued at $80, what inventory cost flow assumption was used? OA. Average costing. O B. FIFO. OC. Weighted average. O D. Specific identification. OE. Retail