What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? William is not playing tennis. If Jessica doesn't sleep, then it is snowing. Jessica is sleeping if and only if William is a doctor. William is a doctor if and only if William is playing tennis.
If Jessica sleeps, then William is a doctor. If William were a doctor, then William is playing tennis. If William were a doctor, then Jessica is sleeping. If William plays tennis, then William is a doctor. William is not a doctor.