Sister Tool Co. is considering investing in specialized equipment costing $613,000. The equipment has a useful life of five years and a residual value of $66,000. Depreciation is calculated using the straight-line method. The expected net cash inflows from the investment are given below: Year 1 2 3 $210,000 151,000 161,000 100,000 139,000 $761,000 4 5 Total What is the average amount invested? O A. $273,500 B. $306,500 C. $380,500 OD. $339,500