What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? There is at least one y for which y will take a plane if and only if y will play tennis. For all y, y will take a plane or y will not play tennis.
For all y, if y plays tennis, then y is taking a plane. There is at least one y for which if y takes a plane, then y is playing tennis. There is at least one y for which if y plays tennis, then y is taking a plane.