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, if x_8 writes a letter, then x_8 is playing a game. For all x_8, x_8 will drive a car if and only if x_8 will play a game. For all x_8, if x_8 drives a car, then x_8 is writing a letter.
For all x_8, if x_8 drives a car, then x_8 is playing a game can be inferred via the universal transitivity rule. For all x_8, if x_8 drives a car, then x_8 is playing a game can be inferred via the universal biconditional elimination rule. For all x_8, if x_8 plays a game, then x_8 is driving a car can be inferred via the universal biconditional elimination rule.