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: forall x_9: Q_3(x_9) <-> U(x_9). forall x_9: U(x_9). forall x_9: Q_9(x_9).
forall x_9: U(x_9) and Q_9(x_9) can be inferred via the universal conjunction rule. forall x_9: Q_9(x_9) and U(x_9) can be inferred via the universal conjunction rule. forall x_9: Q_3(x_9) -> U(x_9) can be inferred via the universal biconditional elimination rule. forall x_9: U(x_9) -> Q_3(x_9) can be inferred via the universal biconditional elimination rule.