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_6, x_6 is a poet. For all x_6, if x_6 makes tea, then x_6 is not a poet. For all x_6, x_6 is a writer if and only if x_6 will make tea.
For all x_6, x_6 will not make tea can be inferred via the universal modus tollens rule. For all x_6, if x_6 were a writer, then x_6 is making tea can be inferred via the universal biconditional elimination rule. For all x_6, if x_6 makes tea, then x_6 is a writer can be inferred via the universal biconditional elimination rule.