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 8.50%; Exxon Mobil bonds yielding 10.50% ; and GM preferred stock with a dividend yield of 9.80%. West's corporate tax rate is 25.00%. What is the after-tax return on the best investment alternative? Assume a 50.00% 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. 8.575% b. 8.985% O c. 8.035% d. 9.331% e. 9.417%