Which of the following statements is/are true? I. Strong form of market efficiency indicates that investors cannot earn abnormal return by analyzing the information they possessed. II. Strong form and semi-strong form of market efficiency are supported by empirical research evidence. III. Semi-strong form of market efficiency indicates that investors could earn abnormal return by trading on private information such as information from within the company. IV. Weak form of market efficiency indicates that investors can not earn abnormal return by trading on technical analysis. I II III and IV are all correct Only I and II are correct Only III and IV are correct Only I III and IV are correct