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 works, then z is a writer. For all z, z is a writer if and only if z will listen to a song. For all z, z will not work. For all z, z will work if and only if z is a writer.
For all z, if z were a writer, then z is listening to a song. For all z, if z works, then z is a writer. For all z, if z listens to a song, then z is a writer. For all z, if z were a writer, then z is working. For all z, z is not a writer.