Solution:(A) Price leadership equilibrium strategy is a Nash Equilibrium strategy: This is correct. In price leadership, the dominant firm sets the price, and the smaller firms follow, maximizing their own profits given the leader's price.
This satisfies the definition of Nash equilibrium.
(B) Bertrand equilibrium strategy is a Nash Equilibrium strategy: This is correct. In the Bertrand model (where firms compete on price), the Nash equilibrium occurs when both firms set their price equal to marginal cost.
(C) Stackelberg equilibrium strategy is a Nash Equilibrium strategy: This is correct. In the Stackelberg model, the leader firm sets its output first, and the follower firm reacts to the leader's output.
Given the leader's output, the follower acts optimally to maximize its own profit, and neither firm regrets its decision. This leads to a Nash equilibrium.
(D) Monopolist equilibrium strategy is a Nash Equilibrium strategy: This is incorrect. A monopolist has no competitors, so the concept of Nash equilibrium (which involves interaction between players) does not apply.
(E) Cournot equilibrium strategy is a Nash Equilibrium strategy: This is correct. In the Cournot model (where firms compete on quantity), each firm chooses its output level, assuming the other firm's output level is fixed.
The resulting intersection of the reaction functions is a Nash equilibrium.