I need answer of these questions ASAP !! PLEASE

3A. What is a dominant strategy equilibrium? Provide an example of a game with a dominant strategy equilibrium, and another one of a game without a dominant strategy equilibrium. 3B. Consider the following two-player two-strategy game, where players are denoted A, B, strategies as s, t and utility functions uA, up are as follows: UA( s, s) = 2, UB(S, s) = 1, uA(s, t) = 1, up(s, t) = 1, uA(t, s) = 1, up(t, s) = 2, uA(t, t) = 2, up(t, t) = 3. Then, if one denotes with a the probabilita that A chooses s, and with y the probability that B chooses s, a Nash equilibrium in (properly) mixed strategies of the game is: (a) x = y = 1/2 and is Pareto inefficient (b) x = 3/4, y = 1/4 and is Pareto efficient (c) x = 1/4, y = 3/4 and is Pareto inefficient (d) x = 3/4, y = 1/4 and is Pareto efficient (e) NOPAC