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_6, x_6 will take a plane if and only if x_6 will drink water. For all x_6, x_6 will take a plane or x_6 will not drink water.
For all x_6, if x_6 drinks water, then x_6 is taking a plane can be inferred via the universal rewriting rule. For all x_6, if x_6 takes a plane, then x_6 is drinking water can be inferred via the universal biconditional elimination rule. For all x_6, if x_6 drinks water, then x_6 is taking a plane can be inferred via the universal biconditional elimination rule.