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 Jessica cooks, then William is a taxi driver. William is a taxi driver if and only if Patricia is a nurse. If William were a taxi driver, then Jessica is cooking.
Jessica is cooking if and only if William is a taxi driver can be inferred via the biconditional introduction rule. William is a taxi driver if and only if Jessica is cooking can be inferred via the biconditional introduction rule. If William were a taxi driver, then Patricia is a nurse can be inferred via the biconditional elimination rule. If Patricia were a nurse, then William is a taxi driver can be inferred via the biconditional elimination rule.