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, if x_6 drinks water, then x_6 is a soldier. For all x_6, if x_6 were a soldier, then x_6 is excited. There is at least one x_6 for which x_6 will drink water if and only if x_6 is excited.
For all x_6, if x_6 drinks water, then x_6 is excited can be inferred via the universal transitivity rule. There is at least one x_6 for which if x_6 drinks water, then x_6 is excited can be inferred via the existential biconditional elimination rule. There is at least one x_6 for which if x_6 were excited, then x_6 is drinking water can be inferred via the existential biconditional elimination rule.