Suppose that your friend brags about his ability to make accurate predictions about financial market movements using only historical returns. He says it is totally pointless to keep track of company earnings. All you need to do is smart statistical analysis of prices and make buy/sell decisions based on that. If it turns out that strategies such as your friend's really achieve superior abnormal returns over longer horizons, financial markets are A. Weak-form efficient B. Strong form efficient C. Not even weak-form efficient D. Semi-strong form efficient