Answer:
The correct answer is letter "B": either weak, semi-strong, or strong.
Step-by-step explanation:
The Efficient Market Hypothesis (EMH) is a theory that states that stocks reflect all the information there is so there is no form investors can beat the market even if having insider information. The EMH establishes then, that technical or fundamental analysis is useless at the moment of "predicting" stock prices.
There are three (3) forms of EMH: weak, semi-strong, and strong. Therefore, if a friend of ours mentions that he cannot beat the market even when having insider information, it implies the market he is trading at is either weak, semi-strong, or strong.