What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? If David were a lawyer, then Barbara is sleeping. If David were a lawyer, then it is not raining. If Barbara sleeps, then David is a lawyer. It is raining and Susan is driving a car.
If Barbara sleeps, then it is not raining. It is raining. Susan is driving a car. David is a lawyer if and only if Barbara is sleeping. Barbara is sleeping if and only if David is a lawyer.