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: There is at least one x_6 for which if x_6 were a janitor, then x_6 is working. For all x_6, x_6 will drink water and x_6 will climb a mountain. For all x_6, if x_6 drinks water, then x_6 is a janitor.
There is at least one x_6 for which if x_6 drinks water, then x_6 is working can be inferred via the existential transitivity rule. For all x_6, x_6 will drink water can be inferred via the universal simplification rule. For all x_6, x_6 will climb a mountain can be inferred via the universal simplification rule.