Pro-Am Audio is a company that is contracted to DJ private events. Due to a recent increase in bookings, Pro-Am is considering the purchase of another mobile DJ unit. Pro-Am uses the payback method to evaluate its investments. The mobile DJ unit will cost $40,000, has a useful life of 10 years, and will generate $5,000 in net cash inflows per year. The residual value of the unit is $800. What is the payback period for the mobile DJ unit? O A. 6.9 years B. 8 years OC. 8.16 years D. 7.84 years