Corey's Campus Store has $3,000 of inventory on hand at the beginning of the month. During the month, the company buys $31,500 of merchandise and sells merchandise that had cost $24,000. At the end of the month, $10,000 of inventory is on hand. How much shrinkage occurred during the month?
1: 3,000
2: 3,500
3: 3,800
4: 4,200