What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? Name the inference rule being used: For all x_6, x_6 will play squash or x_6 will climb a mountain. For all x_6, x_6 will play a game. For all x_6, if x_6 plays squash, then x_6 is not playing a game.
For all x_6, x_6 will not play squash can be inferred via the universal modus tollens rule.