Buy-Rite Pharmacy has purchased a small auto for delivering prescriptions. The auto was purchased for $25,000 and will have a 6-year useful life and a $5,400 salvage value. Delivering prescriptions (which the pharmacy has never done before) should increase gross revenues by at least $33,400 per year. The cost of these prescriptions to the pharmacy will be about $27,800 per year. The pharmacy depreciates all assets using the straight-line method. The payback period for the auto is closest to: