What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? Richard is listening to a song or Susan is not a carpenter. Karen is a musician if and only if Richard is listening to a song.
If Susan were a carpenter, then Richard is listening to a song. If Karen were a musician, then Richard is listening to a song. If Richard listens to a song, then Karen is a musician.