2(20 points) An investor constructs an optimal-portfolio P with two risky stocks X and Y. The expected rate of return of stock X is 15% and standard deviation is 25% and expected return of stock Y is 12% and standard deviation is 20%. The risk-free rate is 5%. The correlation coefficient between the stocks is 0.15. The optimal-portfolio weights of X and Y are 67.04% and 32.96% respectively. A. Compute the expected return and standard deviation of the optimal portfolio. (5 points) B. If the investor wants an expected return of 18% from a complete-portfolio C formed by using the optimal-portfolio P and risk-free rate, what proportion of X, Y, and risk-free asset should the investor invest in the complete portfolio?(5 points)