Company use perpetual average price system. On January 10, a unit bought 600 items for $ 5/item. Then on January 20, it bought 400 items for $ 10 /item. On January 30, the unit released 500 items. What was the cost of issue if the unit had a stock of 100 items at $ 15/ item as of January 1. Select one: O 4500 O 500 O 3500 O 3863,64