Eric wants to sell his car that he paid $7,000 for 3 years ago. The car depreciated, or decreased in value, at a constant rate each month over a 3-year period. If x represents the monthly depreciation amount, which expression shows how much Eric can sell his car for today?

A.7,000 − 3x
B.7,000 + 3x
C.7,000 − 36x
D.7,000 + 36x