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 z, if z cooks, then z is writing a letter. For all z, if z writes a letter, then z is playing a game. If Karen plays a game, then Richard is a soldier. If Richard were a soldier, then Karen is cooking.
If Karen plays a game, then Karen is cooking can be inferred via the transitivity rule. For all z, if z cooks, then z is playing a game can be inferred via the universal transitivity rule.