(20 points) Understand CAPM model: Suppose the 3-month U. Treasury bill (T-bill) rate is 4%, the Standard Poor's 500 Composite Index (SP 500) is...

(20 points) Understand CAPM model: Suppose the 3-month U.S. Treasury bill (T-bill) rate is 4%, the Standard & Poor’s 500 Composite Index (S&P 500) is 12%. An analyst gathered the information about the four common stocks (see the following table). Based on CAPM model, what are the required rates of return for the four stocks respectively? Suppose the Treasury bill rate increase to 6%, what happen to the required rates of return for the four stocks.