Sauer milk inc. wants to determine the minimum cost of capital point for the firm. assume it is considering the following financial plans: cost (aftertax) weights plan a debt 4.0 % 10 % preferred stock 8.0 5 common equity 12.0 85 plan b debt 4.2 % 20 % preferred stock 8.2 5 common equity 13.0 75 plan c debt 5.0 % 30 % preferred stock 10.7 5 common equity 9.6 65 plan d debt 13.0 % 40 % preferred stock 11.6 5 common equity 11.6 55 a-1. compute the weighted average cost for four plans. (do not round intermediate calculations. input your answers as a percent rounded to 2 decimal places.)