What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? For all y, if y were a janitor, then y is drinking water. For all y, y will drink water. There is at least one y for which if y drinks water, then y is a janitor.
There is at least one y for which y is a janitor. There is at least one y for which y will drink water if and only if y is a janitor. There is at least one y for which y is a janitor if and only if y will drink water.