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: John is not an office clerk. If Thomas were not a lawyer, then John is poor. If John were poor, then Joseph is an artist. If Thomas were a lawyer, then John is an office clerk.
Thomas is not a lawyer can be inferred via the modus tollens rule. If Thomas were not a lawyer, then Joseph is an artist can be inferred via the transitivity rule.