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 Charles were a lawyer, then Charles is a doctor. For all x_17, if x_17 were a doctor, then x_17 is a lawyer. Charles is not a lawyer. If Mary were excited, then Jennifer is taking a plane. If Jennifer takes a plane, then Charles is a doctor.
If Mary were excited, then Charles is a doctor can be inferred via the transitivity rule.