Which of the following statements is correct? With a portfolio diversification, the inherent risk that remains is market risk, which is constant for all stocks in the market If a beta of a stock doubles, then its required rate of return must double according to the CAPM The beta of a portfolio is always smaller than the betas of any of the individual securities in the portfolio because of the diversification effect The most effective diversification can be achieved when two stocks with a +1.0 correlation are combined to form a portfolio None of the statements is correct