What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? If John plays a game, then Susan is an artist. For all z, if z listens to a song, then z is an artist. For all z, if z were an artist, then z is listening to a song. John is playing a game or Susan is listening to a song.
If Susan were sad, then John is playing a game. For all z, z will listen to a song if and only if z is an artist. For all z, z is an artist if and only if z will listen to a song.