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: Susan is a police officer if and only if Elisabeth is a taxi driver. Elisabeth is a taxi driver if and only if Susan is a police officer.
If Susan were a police officer, then Elisabeth is a taxi driver can be inferred via the biconditional elimination rule. If Elisabeth were a taxi driver, then Susan is a police officer can be inferred via the biconditional elimination rule. If Elisabeth were a taxi driver, then Susan is a police officer can be inferred via the biconditional elimination rule. If Susan were a police officer, then Elisabeth is a taxi driver can be inferred via the biconditional elimination rule.