What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? For all x_4, x_4 will listen to a song or x_4 is a doctor. There is at least one x_4 for which x_4 will work. For all x_4, if x_4 listens to a song, then x_4 is a bartender. For all x_4, if x_4 were a doctor, then x_4 is a bartender.
For all x_4, x_4 is a bartender.