What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? For all x_12, x_12 is a sailor. There is at least one x_12 for which x_12 will play tennis or x_12 will listen to a song. For all x_12, x_12 will listen to a song if and only if x_12 is a writer. For all x_12, if x_12 plays tennis, then x_12 is a writer.
For all x_12, if x_12 listens to a song, then x_12 is a writer. For all x_12, if x_12 were a writer, then x_12 is listening to a song.