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_9, x_9 will drive a car if and only if x_9 will sleep. For all x_9, x_9 will take a plane or x_9 is a sailor. For all x_9, if x_9 cooks, then x_9 is sleeping. For all x_9, if x_9 were a sailor, then x_9 is cooking. For all x_9, x_9 will not take a plane or x_9 will drive a car.
For all x_9, if x_9 were a sailor, then x_9 is sleeping can be inferred via the universal transitivity rule. For all x_9, x_9 is a sailor or x_9 will drive a car can be inferred via the universal resolution rule. For all x_9, if x_9 drives a car, then x_9 is sleeping can be inferred via the universal biconditional elimination rule. For all x_9, if x_9 sleeps, then x_9 is driving a car can be inferred via the universal biconditional elimination rule.