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 Joseph is a mechanic. If Susan were a scientist, then Thomas is a lawyer. If Joseph were a mechanic, then Susan is a scientist. If Thomas were a lawyer, then it is snowing.
If it snows, then Susan is a scientist can be inferred via the transitivity rule. If Susan were a scientist, then it is snowing can be inferred via the transitivity rule. If Joseph were a mechanic, then Thomas is a lawyer can be inferred via the transitivity rule. If Thomas were a lawyer, then Joseph is a mechanic can be inferred via the transitivity rule.