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 were a nurse, then Mary is a writer. If James were sad, then Mary is a writer. For all x_10, x_10 is a nurse or x_10 is sad. If Mary were a writer, then James is a nurse.
If James were sad, then James is a nurse can be inferred via the transitivity rule.