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: For all x_6, x_6 will drive a car if and only if x_6 will sleep. For all x_6, if x_6 were a lawyer, then x_6 is sleeping. There is at least one x_6 for which x_6 will drive a car.
For all x_6, if x_6 drives a car, then x_6 is sleeping can be inferred via the universal biconditional elimination rule. For all x_6, if x_6 sleeps, then x_6 is driving a car can be inferred via the universal biconditional elimination rule.