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

a. 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.

b. 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.

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

d. 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%