The code enforcement unit of a public safety department has two options for purchasing a new vehicle: a $23,000 four-cylinder sedan that averages 26 mpg or a $28,000 hybrid that averages 47 mpg. Assuming that gasoline will cost $4.00 per gallon, that the vehicle will be driven for 15,000 miles per year and will incur annual maintenance costs of $200, which vehicle should the unit purchase? Further assume the vehicle will be kept for five years with no salvage value and a discount rate of 5%. Does your recommendation change if the vehicle is kept for six years?