What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? William is sad if and only if William is an astronaut. For all x_9, x_9 is an astronaut if and only if x_9 will work. For all x_9, x_9 will not work.
If William were sad, then William is an astronaut. If William were an astronaut, then William is sad. For all x_9, if x_9 were an astronaut, then x_9 is working. For all x_9, if x_9 works, then x_9 is an astronaut. For all x_9, x_9 is not an astronaut.