28. Given the following information and assuming beginning inventory was zero and a periodic inventory system was used, what is the gross profit at the end of the period using the FIFO, LIFO, and average cost methods? Purchases Sales 20 units at $50 15 units at $60 35 units at $40 35 units at $45 85 units at $3085 units at $35 FIFO LIFO Cost Average A) $650 $750 $990 B) $650 $750 $677 C) $677 $650 $677