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 y_2, if y_2 plays a game, then y_2 is making tea. For all y_2, if y_2 makes tea, then y_2 is playing squash. For all y_2, if y_2 plays squash, then y_2 is playing a game. For all y_2, if y_2 plays a game, then y_2 is playing squash.
For all y_2, if y_2 plays a game, then y_2 is playing squash can be inferred via the universal transitivity rule. For all y_2, if y_2 makes tea, then y_2 is playing a game can be inferred via the universal transitivity rule. For all y_2, if y_2 plays squash, then y_2 is making tea can be inferred via the universal transitivity rule. For all y_2, y_2 will play squash if and only if y_2 will play a game can be inferred via the universal biconditional introduction rule. For all y_2, y_2 will play a game if and only if y_2 will play squash can be inferred via the universal biconditional introduction rule.