Which of the following statement contradicts semi-strong form efficiency and strong form efficiency, but not weak form efficiency

a. I made profit on January 15th, when I bought IBM as its price fell by 1%, and re-sold one day after.

b. I make profit, consistently and on a risk-adjusted basis, when I buy stocks for one day each time I observe the following price pattern over the previous 3 days: up by 0.1-0.2%, down by 0.3-0.4%, up by 0.2-0.4%.

c. I make profit, consistently and on a risk-adjusted basis, when I buy stocks each time the Fed announces its economic outlook is positive, and sell a week after.

d. . Employees of firm ABC make profit, consistently and on a risk-adjusted basis, when they trade the stock of their company using their private information.