West Corporation has $50,000 that it plans to invest in marketable securities. The corporation is choosing between the following three equally risky securities: Alachua County tax-free municipal bonds yielding 8.5%; Exxon Mobil bonds yielding 10.5%; and GM preferred stock with a dividend yield of 9.25%. West's corporate tax rate is 17.00%. What is the after-tax return on the best investment alternative? Assume a 70% dividend exclusion for tax on dividends. (Assume the company chooses on the basis of after-tax returns. Round your final answer to 3 decimal places.) a) 8.603% Ob) 7.549% c) 8.778% d) 7.462% e) 7.110%