Consider the prisoner's dilemma game below:

	X	Y
A	8,8	0,10
B	10,0	1,1

Throughout this question assume that there is a per-period discount rate d, 0

a) If this stage game is repeated 10 times there is a unique SPNE of the repeated game. Describe the strategy of each player in the SPNE.

b) Now suppose that the stage game is infinitely repeated. What level of d can support a simple trigger strategy as a SPNE?