What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? William is not sleeping. William is sleeping if and only if it is cloudy. If Elisabeth plays tennis, then it is cloudy. Elisabeth is playing tennis or it is not cloudy.
If it is cloudy, then Elisabeth is playing tennis. If William sleeps, then it is cloudy. If it is cloudy, then William is sleeping. It is not cloudy.