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: There is at least one x_17 for which x_17 is not a sailor. For all x_17, if x_17 plays a game, then x_17 is rich. For all x_17, x_17 is rich or x_17 will drink water. For all x_17, if x_17 were rich, then x_17 is playing a game. For all x_17, if x_17 plays a game, then x_17 is a sailor.
There is at least one x_17 for which x_17 will not play a game can be inferred via the existential modus tollens rule. For all x_17, if x_17 were rich, then x_17 is a sailor can be inferred via the universal transitivity rule. For all x_17, x_17 will play a game if and only if x_17 is rich can be inferred via the universal biconditional introduction rule. For all x_17, x_17 is rich if and only if x_17 will play a game can be inferred via the universal biconditional introduction rule.