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 play tennis. For all x_9, if x_9 works, then x_9 is not playing tennis. For all x_9, x_9 will work or x_9 is a carpenter. For all x_9, x_9 is happy.
For all x_9, x_9 will not work can be inferred via the universal modus tollens rule. For all x_9, x_9 will play tennis and x_9 is happy can be inferred via the universal conjunction rule. For all x_9, x_9 is happy and x_9 will play tennis can be inferred via the universal conjunction rule.