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_3, if x_3 were a server, then x_3 is an office clerk. There is at least one x_3 for which x_3 is sad or x_3 is not an office clerk.
There is at least one x_3 for which if x_3 were an office clerk, then x_3 is sad can be inferred via the existential rewriting rule.