What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? For all x_12, x_12 is rich if and only if x_12 is a lawyer. For all x_12, x_12 will not drive a car. David is a lawyer if and only if William is a doctor. For all x_12, x_12 will drive a car if and only if x_12 is rich.
If David were a lawyer, then William is a doctor. If William were a doctor, then David is a lawyer. For all x_12, if x_12 were rich, then x_12 is a lawyer. For all x_12, if x_12 drives a car, then x_12 is rich. For all x_12, if x_12 were a lawyer, then x_12 is rich. For all x_12, if x_12 were rich, then x_12 is driving a car. For all x_12, x_12 is not rich.