If markets are efficient, what should be the correlation coefficient between stock returns for two nonoverlapping time periods?

Question #$1$: $"$If all securities are fairly priced, all must offer equal expected rates of return." Comment and explain

Question #$2$: "Constantly fluctuating stock prices suggest that the market does not know how to price stocks." Respond

Question #$3$: "Large investors $($like a big mutual fund company like T Rowe Price$)$ are believed to have an advantage over smaller investors due to their sizeable resources so this should lead to a consistent active management return premium" Do you agree or disagree?$$ Use Efficient Market Theory to help with your answer.