Which of the following observations would provide evidence against the semi-strong form of the efficient market theory? Explain why or why not for each observation.

a) Mutual fund managers do not on average make superior returns.

b) It is not possible to make superior profits by buying or selling stocks after the announcement of an abnormal decrease in earnings.

c) High P/E stocks tend to have negative abnormal returns.

d) In any year approximately 50% of pension funds outperform the market.