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 y_1 for which y_1 will climb a mountain if and only if y_1 will make tea. For all y_1, if y_1 listens to a song, then y_1 is making tea. For all y_1, y_1 will listen to a song or y_1 will not drive a car. For all y_1, if y_1 climbs a mountain, then y_1 is cooking.
For all y_1, if y_1 drives a car, then y_1 is listening to a song can be inferred via the universal rewriting rule. There is at least one y_1 for which if y_1 climbs a mountain, then y_1 is making tea can be inferred via the existential biconditional elimination rule. There is at least one y_1 for which if y_1 makes tea, then y_1 is climbing a mountain can be inferred via the existential biconditional elimination rule.