Which of the following price discrimination schemes involves both the most extraction of surplus to profit and the highest cost to implement? (Learning objectives 5 and 10) Country B Co Ch Co $2,$2 0,$4 Country A Ch $4,$0 $1,$1 Figure 1: International prisoner's dilemma matrix If played one-shot and the end period is common knowledge, (collusion, cheat) is a Nash equilibrium If played one-shot and the end period is common knowledge, (collusion, collusion) is a Nash equilibrium if played repeatedly and the end period is common knowledge, collusion can be sustained as a Nash equilibrium If played repeatedly and the end period is unknown, collusion can be sustained Nash equilibrium