ISE 211 - HW 4 ELIT 7. The Department of Defense is considering three sites in the National Wildlife Preserve for extraction of rare metals. The cash flows associated with each site are summarized. The extraction period is limited to 7 years and the interest rate is 8% per year. Use the B/C method to determine which site, if any, is acceptable. The monetary unit is $ million. Site A B C Initial Cost, $ 5 12 20 Annual Cost, $/Year 3 5 6 Annual Benefits, $/Year 29 61 Annual Disbenefits, $/ 2 N Year