What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? There is at least one z for which z is a cashier if and only if z is a writer. For all z, if z makes tea, then z is a writer. For all z, if z were a writer, then z is making tea.
For all z, z will make tea if and only if z is a writer. For all z, z is a writer if and only if z will make tea. There is at least one z for which if z were a cashier, then z is a writer. There is at least one z for which if z were a writer, then z is a cashier.