Martock Company uses the periodic inventory system. The following information is available for the period ending December 31:(1) Sales: $30,000 (2) Beginning inventory: $17,500 (3) Ending inventory: $8,000 (4) Purchases: $10,000The cost of goods sold for the period is

a) $21,500

b) $25,100

c) $19,500

d) $26,000

e) $24,500