What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? Robert is not driving a car. William is reading a book. William is a lawyer if and only if Robert is driving a car. If it is overcast, then William is a lawyer.
Robert is not driving a car and William is reading a book. William is reading a book and Robert is not driving a car. If William were a lawyer, then Robert is driving a car. If Robert drives a car, then William is a lawyer. William is not a lawyer.