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: January 12 January 19 January 20: January 27: Balance: 18 units at $13 Purchased 30 units at $14 Sold 24 units at $17 Purchased 24 units at $17 Sold 27 units If the ending inventory is valued at $357, what inventory cost flow assumption was used? Select one: A. Specific identification. B. Retail. C. FIFO. D. Weighted average. E. Average costing