A dominant-strategy equilibrium exists in a game when:

A) no player has a choice.
B) every player has a clear best action that does not depend on the action of the other players.
C) each player's choices are dependent on the actions of other players.
D) no player is able to dictate or predict the actions of any other player.

In a dominant-strategy equilibrium, each player has a clear best action that does not depend on the actions of other players. Option A is incorrect because players always have a choice. Option C is incorrect because a dependent-strategy equilibrium exists when players' choices are dependent on the actions of other players. Option D is incorrect because although players may not be able to predict the actions of other players, a dominant-strategy equilibrium still exists as long as each player has a clear best action.