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 it snows, then Sarah is a bartender. If Sarah were a bartender, then Barbara is an astronaut. It is snowing or Barbara is not an astronaut.
If it snows, then Barbara is an astronaut can be inferred via the transitivity rule. If Barbara were an astronaut, then it is snowing can be inferred via the rewriting rule.