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_5, x_5 will drive a car or x_5 will read a book. For all x_5, if x_5 reads a book, then x_5 is not sad. For all x_5, x_5 is sad. There is at least one x_5 for which x_5 will not drive a car or x_5 is a poet.
For all x_5, x_5 will not read a book can be inferred via the universal modus tollens rule. There is at least one x_5 for which x_5 will read a book or x_5 is a poet can be inferred via the existential resolution rule.