The answer is E but why?

25. Your quantitative research team at Technical Investment Strategies LLC reports that they identified a successful trading strategy. The team claims that superior returns could be achieved by purchasing Canadian stocks whose price has increased at a higher rate than the increase in the Toronto Stock Exchange S&P/TSX stock market index over the past six month. If true, the existence of such a trading strategy would be evidence... a. against the stock market being strong form efficient. b. against the stock market being semi-strong form efficient. c. against the stock market being weak form efficient. d. Both (a) and (b) e. All (a), (b) and (c)