Assume that you manage a risky portfolio with an expected rate of return of 23% and a standard deviation of 43%. The T-bill rate is 3%. Your risky portfolio includes the following investments in the given proportions: Your client decides to invest in your risky portfolio a proportion (y) of his total investment budget with the remainder in a T-bill money market fund so that his overall portfolio will have an expected rate of return of 21%. a. What is the proportion y? b. What are your client's investment proportions in your three stocks and the T-bill fund? c. What is the standard deviation of the rate of return on your client's portfolio