Which statement about portfolio diversification is correct? P-968

a. Efficient diversification can reduce or eliminate systematic risk.

b. Diversification reduces the portfolio’s expected return because it reduces a portfolio’s total risk.

c. As more securities are added to a portfolio, total risk typically can be expected to fall at a decreasing rate.

d. The risk-reducing benefits of diversification do not occur meaningfully until at least 30 individual securities are included in the portfolio.