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: If William drives a car, then David is not sleeping. Thomas is drinking water if and only if Charles is a carpenter. David is sleeping. Thomas is drinking water if and only if William is driving a car.
William is not driving a car can be inferred via the modus tollens rule. If Thomas drinks water, then Charles is a carpenter can be inferred via the biconditional elimination rule. If Thomas drinks water, then William is driving a car can be inferred via the biconditional elimination rule. If Charles were a carpenter, then Thomas is drinking water can be inferred via the biconditional elimination rule. If William drives a car, then Thomas is drinking water can be inferred via the biconditional elimination rule.