Solve the Problem $v=c-c r t$ in This Formula $v$ Is the Present Value

Solve the problem.
-The formula for finding the present value of an item that depreciates yearly is $v=c-c r t$ . In this formula, $v$ is the present value, $c$ is the original cost, $r$ is the rate of depreciation per year, and $t$ is the number of years that have passed. After 7 years, what is the value of a car originally costing $\$ 27,000$ that depreciated at a rate of 0.1 per year?

A) $\$ 45,900$
B) $\$ 18,900$
C) $\$ 8100$
D) $\$ 0$