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