What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? Sarah is a scientist if and only if Karen is playing tennis. William is a nurse if and only if Sarah is a scientist.
If Sarah were a scientist, then Karen is playing tennis. If William were a nurse, then Sarah is a scientist. If Karen plays tennis, then Sarah is a scientist. If Sarah were a scientist, then William is a nurse.