Which of the following statement(s) is correct? 1. As every player chooses a dominant strategy in a game of two players, these strategies achieve a social optimal. 2. Both players in a game may not have dominant strategies but must have at least one best response to the other player. 3. Mixed strategy equilibrium is achieved when, the strategy of each player is selected under their respective probability distribution; no player is capable of improving his own payoff by unilateral change. 4. The spirit of mixed strategy equilibrium is to make the behavior of the player unpredictable by the other player through randomizing the probability in strategy selection. As such, one can only choose one probability distribution between 2 pure strategies so that there is no difference in payoff