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: For all z, if z were a carpenter, then z is a taxi driver. For all z, z is a taxi driver or z is not a carpenter. For all z, z is a taxi driver if and only if z is a carpenter.
For all z, if z were a carpenter, then z is a taxi driver can be inferred via the universal rewriting rule. For all z, if z were a taxi driver, then z is a carpenter can be inferred via the universal biconditional elimination rule. For all z, if z were a carpenter, then z is a taxi driver can be inferred via the universal biconditional elimination rule.