What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? Jessica is not listening to a song. For all x_12, if x_12 takes a plane, then x_12 is an office clerk. If Jessica listens to a song, then Karen is an office clerk. If Karen were an office clerk, then Jessica is listening to a song.
Karen is not an office clerk.