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 plays squash, then y is a police officer. For all y, y will not play tennis. For all y, if y were a police officer, then y is playing squash. There is at least one y for which y is a police officer if and only if y will play tennis.
For all y, y will play squash if and only if y is a police officer. For all y, y is a police officer if and only if y will play squash. There is at least one y for which if y were a police officer, then y is playing tennis. There is at least one y for which if y plays tennis, then y is a police officer. There is at least one y for which y is not a police officer.