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_9, x_9 is fast or x_9 will drink water. There is at least one x_9 for which x_9 is a nurse if and only if x_9 will drink water. For all x_9, x_9 is not fast.
For all x_9, x_9 will drink water can be inferred via the universal disjunctive syllogism rule. There is at least one x_9 for which if x_9 were a nurse, then x_9 is drinking water can be inferred via the existential biconditional elimination rule. There is at least one x_9 for which if x_9 drinks water, then x_9 is a nurse can be inferred via the existential biconditional elimination rule.