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: If James reads a book, then Robert is a writer. For all z_2, if z_2 were a writer, then z_2 is playing a game. If Robert plays a game, then James is reading a book.
If Robert plays a game, then Robert is a writer can be inferred via the transitivity rule.