Which one of the following statements is correct? Select one: a. When weighted average is used in a perpetual system, average cost is recalculated after each purpose if the unit purchase cost changes O b. When FIFO is used, ending inventory is different in periodic and perpetual systems O c. When the weighted average method is used, ending inventory is the same in periodic and perpetual systems O d. When FIFO is used in a periodic system, average cost is recalculated after each purpose if the unit purchase cost changes O e. When weighted average is used in a periodic system, a new average cost is recalculated after each purpose if the unit purchase cost changes