Power Inc. purchased inventory as follows: (Past Exam) November 1 2500 units at $15 November 3 1750 units at $22 November 9 2000 units at $20 On November 12, Power Inc. sold 4000 units for $42 each. The average unit cost to be used for the cost of goods sold on November 12, in a perpetual inventory system, is OA) $18 B) $17.88 C) $18.50 D) $18.56