What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? For all y_3, if y_3 climbs a mountain, then y_3 is a police officer. For all y_3, y_3 will not climb a mountain. For all y_3, if y_3 were a police officer, then y_3 is climbing a mountain.
For all y_3, y_3 is not a police officer. For all y_3, y_3 will climb a mountain if and only if y_3 is a police officer. For all y_3, y_3 is a police officer if and only if y_3 will climb a mountain.