CDX Inc., uses a periodic inventory system. Consider the following summarized transactions and selected information for CDX's most recently completed fiscal year: Gross purchases (all on account) $71,709 Purchases returns and allowances 2,000 Merchandise inventory, January 1 15.000 Merchandise inventory, December 31 19,000 Cash payment to suppliers 52.000 Based on these details, the cost of sales for the year is: O A. $67,700 OB. $13,700 O C. $65.700 O D. $48,000