Assume that you manage a risky portfolio with an expected rate of return of 17% and a standard deviation of 27%. The T-bill rate is 7%. Your risky portfolio includes the following investments in the given proportions: Stock A 27 % Stock B 33 Stock C 40 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 15%. What is the standard deviation of the rate of return on your client's portfolio