Which Statement About Portfolio Diversification Is Correct

Which statement about portfolio diversification is correct?

A) Proper diversification can reduce or eliminate systematic risk.
B) The risk-reducing benefits of diversification do not occur meaningfully until at least 50-60 individual securities have been purchased.
C) Because diversification reduces a portfolio's total risk,it necessarily reduces the portfolio's expected return.
D) Typically,as more securities are added to a portfolio,total risk would be expected to decrease at a decreasing rate.
E) None of these statements are correct.