[1-4] There is an investment opportunity set where the optimal risky portfolio O has expected rate of return of 12% and volatility or standard deviation) of 25%, and T-bill yields a risk free rate of 2%. 1. Investor A chooses to invest 75 % in the portfolio O and 25% in T-bill. Compute the expected return and volatility of her portfolio, and its Sharpe ratio. 2. Investor B has an expected risk premium of 7% to the risk-free asset return with her portfolio Compute the composition of her portfolio and its Sharpe ratio. 3. Investor C has a volatility target of 20%. Compute the expected return and its Sharpe ratio. 4. Draw a CAL line and mark Sharpe ratio and all investors' asset allocation choices(A, B, C)