Will is debating how much he should spend on his new truck. On the one hand, he hasn't made any major purchases in several years and he really wants to treat himself and enjoy his vehicle. On the other hand, he feels that he should save the money and put it into his retirement account rather than spending on something that depreciates in value very quickly.

Therefore, he's trying to look at all of the factors that play a role in determining a monthly car loan payment. Which of the following factors is not related to a vehicle's loan payment?

a) The length of the lease agreement

b) The required down payment and the previous vehicle's trade-in value