Trader sells 15 units for $25 each on December 15. Eight of the sold units are from the December 7 purchase and seven are from the December 14 purchase. Trader uses a perpetual inventory system. Determine the costs assigned to the December 31 ending inventory when costs are assigned based on
(a) FIFO,
(b) LIFO,
(c) weighted average, and
(d ) specific identification