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_14, x_14 will drink water if and only if x_14 will take a plane. For all x_14, x_14 will take a plane or x_14 is not rich. There is at least one x_14 for which x_14 will drink water or x_14 is a doctor. For all x_14, x_14 is a doctor if and only if x_14 is rich.
For all x_14, if x_14 were rich, then x_14 is taking a plane can be inferred via the universal rewriting rule. For all x_14, if x_14 drinks water, then x_14 is taking a plane can be inferred via the universal biconditional elimination rule. For all x_14, if x_14 were a doctor, then x_14 is rich can be inferred via the universal biconditional elimination rule. For all x_14, if x_14 takes a plane, then x_14 is drinking water can be inferred via the universal biconditional elimination rule. For all x_14, if x_14 were rich, then x_14 is a doctor can be inferred via the universal biconditional elimination rule.