The expected rate of return of a portfolio of risky securities is the weighted sum of the securities' variances the sum of the securities' covariances the sum of the securities' variances the weighted sum of the securities' expected returns

Option D. The weighted sum of the expected returns on the securities. This is the expected rate of return of the portfolio of securities that is expected to be realized from an investment, the average value of the probability distribution of the possible results. This is a way of measuring risk through the coefficient of variation, which is the standard deviation between the expected return.