Which statement about portfolio diversification is correct? Proper diversification can reduce or eliminate systematic risk. The risk-reducing benefits of diversification do not occur meaningfully until at least 10-15 individual securities have been purchased. Because diversification reduces a portfolio's total risk, it necessarily reduces the portfolio's expected return. Typically, as more securities are added to a portfolio, total risk would be expected to decrease at a decreasing rate. O Diversification cannot reduce firm-specific risk