Which of the Following Statements Is False

Which of the following statements is false?

A) When stocks are perfectly positively correlated, the set of portfolios is identified graphically by a straight line between them.
B) An investor seeking high returns and low volatility should only invest in an efficient portfolio.
C) When the correlation between securities is less than 1, the volatility of the portfolio is reduced due to diversification.
D) Efficient portfolios can be easily ranked, because investors will choose from among them those with the highest expected returns.