What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? For all x_17, if x_17 plays tennis, then x_17 is sleeping. If David sleeps, then Karen is a bartender. David is sleeping. If Karen were a bartender, then David is playing tennis.
If David sleeps, then David is playing tennis. There is at least one x for which x will sleep.