What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? For all z, if z were a politician, then z is listening to a song. There is at least one z for which if z listens to a song, then z is a politician. For all z, z is a politician if and only if z will listen to a song.
There is at least one z for which z will listen to a song if and only if z is a politician. There is at least one z for which z is a politician if and only if z will listen to a song. For all z, if z were a politician, then z is listening to a song. For all z, if z listens to a song, then z is a politician.