(Ignore income taxes in this problem.) Buy-Rite Pharmacy has purchased a small auto for delivering prescriptions. The auto was purchased for $21,000 and will have a 6-year useful life and a $5,000 salvage value. Delivering prescriptions (which the pharmacy has never done before) should increase gross revenues by at least $33,000 per year. The cost of these prescriptions to the pharmacy will be about $27,000 per year. The pharmacy depreciates all assets using the straight-line method. The payback period for the auto is closest to:

a. 4.3 years

b. 3.5 years

c. 4.5 years

d. 2.7 years