Consider the game in the attached picture, here the game is between two players, A and B, where each player has two strategies. Cooperate (C) or Defect(D)

Now suppose there is always a chance of ? that this game is going to be played again after each stage

a.) For which values of ? "Grim Trigger Strategy" is a SPE and sustains cooperation?

Explain by defining the Grim Trigger Strategy.

b.) Is always cooperate a SPE? Explain