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 will make tea if and only if z will work. For all z, z will work if and only if z will make tea.
For all z, if z works, then z is making tea. There is at least one z for which if z makes tea, then z is working. For all z, if z makes tea, then z is working. There is at least one z for which if z works, then z is making tea.