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_11, if x_11 were a server, then x_11 is not poor. There is at least one x_11 for which x_11 will take a plane. For all x_11, if x_11 takes a plane, then x_11 is poor. For all x_11, if x_11 were rich, then x_11 is a server.
There is at least one x_11 for which x_11 is poor can be inferred via the existential modus ponens rule.