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 rains, then Jessica is cooking. For all x_20, if x_20 were a carpenter, then x_20 is an artist. If Jessica cooks, then Sarah is a carpenter. It is raining if and only if Linda is a server.
If it rains, then Sarah is a carpenter can be inferred via the transitivity rule. If it rains, then Linda is a server can be inferred via the biconditional elimination rule. If Linda were a server, then it is raining can be inferred via the biconditional elimination rule.