A driver entering into a car lease agreement can obtain the right to buy the car in 4 years for $\$ 10,000$. The current value of the car is $\$ 30,000$. The value of the car, $S$, is expected te follow the process
$$
d S=\mu S d t+\sigma S d z
$$
where $\mu=-0.25, \sigma=0.15$, and $d z$ is a Wiener process. The market price of risk for the car price is estimated to be $-0.1$. What is the value of the option? Assume that the riskfree rate for all maturities is $6 \%$.