What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? For all x_5, if x_5 were a police officer, then x_5 is listening to a song. For all x_5, x_5 will not listen to a song. There is at least one x_5 for which x_5 is a police officer.
Since the premises are contradictory, we can infer anything from them.