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_7 for which if x_7 were a server, then x_7 is not drinking water. For all x_7, x_7 is a server or x_7 is not happy. For all x_7, x_7 will drink water.
There is at least one x_7 for which x_7 is not a server can be inferred via the existential modus tollens rule. For all x_7, if x_7 were happy, then x_7 is a server can be inferred via the universal rewriting rule.