Duncan is about to buy a new car for $25,000 from Ninas Beaters and Lemons used car lot. Nina has given Duncan two options: a. An monthly installment loan for the full amount for a term of 5 years at 3.9%; or b. Pay cash plus a blueberry fritter and she will give him an instant cash rebate of $3,000. Duncan knows that he can borrow the money from Ryans Rip-Off Finance company at a rate of 9% for 5 years.

Which option should he take and why? Show your work!