Hello, I need to figure out whether the games when players only play C and in the other game only play D are the subgame-perfect Nash equilibria. Is it just simply no for when players play C and yes when play D?

1. Assuming that the discount rate o = 0.99, check whether the strategy profiles below are subgame-perfect Nash equilibria in the infinitely repeated game where the stage game is the following prisoners' dilemma game: [C is cooperate with each other; D is don't cooperate with each other] Player1 / Player 2 Cooperate (C) Don't Cooperate (D) Cooperate (C) 5, 5 0, 6 Don't Cooperate (D) 6, 0 1, 1