As the number of stocks in a portfolio increases:

A the expected return decreases

B the expected return increases

C the nonsystematic risk of the portfolio decreases

D the systematic risk of the portfolio increases

Which of the following is most true regarding diversification?

a it is of little use to investors who wish to earn large returns

b it can greatly increase the risk of a portfolio

c it has become less popular after the great recession

d it decreases the overall risk of a portfolio