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 y for which if y makes tea, then y is a writer. For all y, if y makes tea, then y is a writer. For all y, if y were a writer, then y is making tea.
For all y, y will make tea if and only if y is a writer. For all y, y is a writer if and only if y will make tea. There is at least one y for which y will make tea if and only if y is a writer. There is at least one y for which y is a writer if and only if y will make tea.