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: If Karen takes a plane, then Patricia is a janitor. For all x_13, x_13 is a janitor if and only if x_13 will drink water. Karen is taking a plane.
Patricia is a janitor can be inferred via the modus ponens rule. For all x_13, if x_13 were a janitor, then x_13 is drinking water can be inferred via the universal biconditional elimination rule. For all x_13, if x_13 drinks water, then x_13 is a janitor can be inferred via the universal biconditional elimination rule.