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_12, if x_12 were fast, then x_12 is taking a plane. For all x_12, if x_12 takes a plane, then x_12 is sad. For all x_12, x_12 will play a game or x_12 is fast. For all x_12, if x_12 were sad, then x_12 is drinking water. For all x_12, if x_12 plays a game, then x_12 is taking a plane.
For all x_12, if x_12 were fast, then x_12 is sad can be inferred via the universal transitivity rule. For all x_12, if x_12 takes a plane, then x_12 is drinking water can be inferred via the universal transitivity rule. For all x_12, if x_12 plays a game, then x_12 is sad can be inferred via the universal transitivity rule. For all x_12, x_12 will take a plane can be inferred via the universal disjunction elimination rule.