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 y, if y were a police officer, then y is a bartender. For all y, y is not a bartender. Michael is taking a plane if and only if Patricia is a police officer. For all y, if y were a bartender, then y is a police officer.
If Michael takes a plane, then Patricia is a police officer can be inferred via the biconditional elimination rule. If Patricia were a police officer, then Michael is taking a plane can be inferred via the biconditional elimination rule. For all y, y is not a police officer can be inferred via the universal modus tollens rule. For all y, y is a police officer if and only if y is a bartender can be inferred via the universal biconditional introduction rule. For all y, y is a bartender if and only if y is a police officer can be inferred via the universal biconditional introduction rule.