What is the cxpccted rate of return on a portfolio that has S4.000 invested in Stock A and $6,000 invested in Stock B? The expected rates of return on these two stocks arc 13 percent and 9 percent, respectively. A two-stock portfolio has 30 percent in Stock A, with an expected return of 21 percent and a standard deviation of 5 percent, and the remainder in Stock B. with an 18 percent expected return and a standard deviation of 2 percent. The correlation coefficient is 0.6. Determine the standard deviation for this portfolio