The payoff matrix below depicts a two-person game known as the "Prisoner's Dilemma". The entries in the matrix cells are players' payoffs (the first entry is the Row player's payoff, while the second entry is the Column player's payoff).

(a) Find the pure-strategy equilibrium of the Prisoner's Dilemma. Find the predicted probability of cooperation i.e. the frequency of C choices by individual players. Define payoff efficiency as the sum of row and column player payoffs, normalized so that the maximum possible joint payoff has an efficiency of one and the minimum possible joint payoff has efficiency of zero. Find the predicted payoff efficiency.

C D

C 70,70 10,80

D 80,10 40,40