Which of the following statements contradicts semi$-$strong form efficiency?

I make profit, consistently and on a risk$-$adjusted basis, when I buy Wal$-$Mart stocks when it makes a positive

earnings announcement, and sell a week after.

I make profit from time to time, if I short$-$sell Yahoo at the end of a day when its price increases, and close my

short position one day after.

CEO of firm ABC makes profit, consistently and on a risk$-$adjusted basis, by using his inside information when he

trades the stock of ABC.

I make an expected return larger than the market return when I form a portfolio that is long stocks from Northern

California, and short stocks from Southern California.