An electronic circuit board manufacturer is considering six mutually exclusive cost reduction projects for one of its PC-board manufacturing plants - either Plant A or Plant B as indicated. All have lives of 10 years and zero salvage values. The required investment and the estimated after-tax cash flow returns are shown in the table below for each alternative. For the particular plant shown the projects are put in order of increasing investment to facilitate the IRR incremental analysis based on an MARR of 15%: Plant A Proposal Aj Required Investment After-tax savings IRR (%) From the table above, the IRR of Proposal A6 is: a) 24% b) 35% c) 25% d) 27% e) 40%