Rockford Development has the following mix of financing available Proportion Cost Debt financing 40% 9% Preferred tock 10% 13% Common stock 25% 12% Retained earnings 25% 12% Rockford is considering the following projects: Return Project A 11.40% Project B 11.25% Project C 11.00% Project D 10.90% Project E 10.90% Project F 10.40% Required: a. What is Rockford's cost of capital? b. Given an unlimited budget, which project should Rockford accept?