Which of the Following Statements Best Describes the Efficient Markets

Which of the following statements best describes the efficient markets hypothesis?

A) If the stock market is weak-form efficient, then one cannot outperform the market even if he or she has private information.
B) If the stock market is semistrong-form efficient, then the expected return on stocks and bonds must be the same.
C) If the stock market is strong-form efficient, then high beta stocks must have the same expected return as low beta stocks.
D) Even though the Efficient Markets Hypothesis (EMH) assumes that markets behave as if all investors were rational, under the EMH it is still possible to have some irrational investors in a rational market.