What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? Name the inference rule being used: If Barbara were a nurse, then Elisabeth is driving a car. It is not overcast. It is overcast if and only if Elisabeth is driving a car. Elisabeth is driving a car or it is not overcast.
If it is overcast, then Elisabeth is driving a car can be inferred via the rewriting rule. If it is overcast, then Elisabeth is driving a car can be inferred via the biconditional elimination rule. If Elisabeth drives a car, then it is overcast can be inferred via the biconditional elimination rule. Elisabeth is not driving a car can be inferred via the biconditional elimination rule.