What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? Sarah is driving a car if and only if Thomas is an electrician. William is sad if and only if Thomas is an electrician. William is sad or Sarah is driving a car.
If Sarah drives a car, then Thomas is an electrician. If William were sad, then Thomas is an electrician. If Thomas were an electrician, then Sarah is driving a car. If Thomas were an electrician, then William is sad.