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_8, x_8 is a janitor and x_8 will sleep. For all x_8, x_8 will drive a car if and only if x_8 is a janitor.
For all x_8, x_8 is a janitor can be inferred via the universal simplification rule. For all x_8, x_8 will sleep can be inferred via the universal simplification rule. For all x_8, if x_8 drives a car, then x_8 is a janitor can be inferred via the universal biconditional elimination rule. For all x_8, if x_8 were a janitor, then x_8 is driving a car can be inferred via the universal biconditional elimination rule.