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_5, if x_5 plays a game, then x_5 is happy. For all x_5, x_5 will play a game or x_5 will not write a letter. For all x_5, if x_5 were happy, then x_5 is curious.
For all x_5, if x_5 plays a game, then x_5 is curious can be inferred via the universal transitivity rule. For all x_5, if x_5 writes a letter, then x_5 is playing a game can be inferred via the universal rewriting rule.