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 x_4, x_4 will not take a plane. For all x_4, x_4 will make tea or x_4 is a police officer. For all x_4, x_4 will make tea if and only if x_4 will take a plane.
For all x_4, if x_4 makes tea, then x_4 is taking a plane can be inferred via the universal biconditional elimination rule. For all x_4, if x_4 takes a plane, then x_4 is making tea can be inferred via the universal biconditional elimination rule. For all x_4, x_4 will not make tea can be inferred via the universal biconditional elimination rule.