4. The total market value of the common stock of the Okenfenokee Real Estate Company is $6 million, and the total value of its debt of $4 million. The treasurer estimates that the beta of the stock is currently 1.5 and that the expected risk premium on the market is 10%. The Treasury bill rate is 8%. a. What is the required return on Okenfenokee stock? b. What is the beta of the company's existing portfolio of assets? c. Estimate the company's cost of capital d. Estimate the discount rate for an expansion of the company's present business