What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? For all x_9, x_9 is a musician. For all x_9, if x_9 were a musician, then x_9 is a sailor. For all x_9, x_9 will take a plane or x_9 will write a letter. There is at least one x_9 for which if x_9 takes a plane, then x_9 is not a sailor.
For all x_9, x_9 is a sailor.