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 Jennifer were a doctor, then Robert is taking a plane. Jennifer is not driving a car or Michael is playing a game. For all x_13, x_13 will write a letter or x_13 will drive a car. If Michael plays a game, then Sarah is reading a book. For all x_13, x_13 will not write a letter or x_13 is a doctor. If Sarah reads a book, then Robert is taking a plane.
If Michael plays a game, then Robert is taking a plane can be inferred via the transitivity rule. For all x_13, x_13 will drive a car or x_13 is a doctor can be inferred via the universal resolution rule.