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 Sarah were a musician, then James is rich. If David takes a plane, then Sarah is a musician. If James were rich, then David is taking a plane. For all x_12, x_12 is not rich.
If David takes a plane, then James is rich can be inferred via the transitivity rule. If James were rich, then Sarah is a musician can be inferred via the transitivity rule.