What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? If Sarah were an office clerk, then John is listening to a song. For all x_4, if x_4 listens to a song, then x_4 is not a writer. For all x_4, x_4 is a writer.
For all x_4, x_4 will not listen to a song.