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: There is at least one x_5 for which x_5 is happy or x_5 is a doctor. For all x_5, if x_5 sleeps, then x_5 is playing a game. For all x_5, x_5 will not play a game. For all x_5, if x_5 were happy, then x_5 is sleeping.
For all x_5, x_5 will not sleep can be inferred via the universal modus tollens rule. For all x_5, if x_5 were happy, then x_5 is playing a game can be inferred via the universal transitivity rule.