Alice and Betsy are playing a game in which each can play either of two strategies, leave or stay. If both play the strategy leave, then each gets a payoff of $300. If both play the strategy stay, then each gets a payoff of $600. If one plays stay and the other plays leave, then the one who plays stay gets a payoff of $C and the one who plays leave gets a payoff of $D. For which values of C and/or D is the outcome (leave, leave) a Nash equilibrium?