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, if x were excited, then x is a writer. There is at least one x for which if x were a mechanic, then x is working. For all x, x is excited or x is a mechanic. For all x, if x were a writer, then x is working.
For all x, if x were excited, then x is working can be inferred via the universal transitivity rule.