13.1 Which well-known standard game are these rms playing? [1] 13.2 Explain what the Grim strategy is in the context of this game. [2] 13.3 If these rms have been cooperating for a number of years, and it is known that iPear is playing a Tit-for-Tat strategy, and Wongsun's annual discount rate is 10 per cent, would it be rational for Wongsun to stop cooperating for one period only in order to try to exploit iPear's cooperative strategy? Show calculations. [3]