What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? For all x_11, if x_11 were a janitor, then x_11 is a police officer. For all x_11, x_11 is not a janitor. For all x_11, if x_11 were a police officer, then x_11 is a janitor. For all x_11, x_11 is a police officer and x_11 is happy.
Since the premises are contradictory, we can infer anything from them.