Which of the following observations would appear to violate the weak form of EMH? Semi-strong form? Strong form? Please explain every scenario.

a. The average rate of return is significantly greater than zero.

b. The correlation between the return during a given week and the return during the following week is zero.

c. One could have made superior return by buying stock after a 10% rise in price and selling after a 10% fall.

d. One could have made higher-than-average capital gains by buying those stocks with low dividend yields (i.e., dividend/price, and information regarding dividends is normally disclosed in the annual reports).