Assuming that a perpetual inventory system is used, what is the cost of goods sold on a LIFO basis for July?

Tamarisk has the following inventory data: July 1 Beginning inventory 5 Purchases 14 Sale 21 Purchases 30 Sale 31 units at $6.20 125 units at $6.90 83 units 62 units at $7.50 58 units Assuming that a perpetual inventory system is used, what is the cost of goods sold on a LIFO basis for July? $1007.70 $744.00 $1519.70 $512.00