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_15, if x_15 were a poet, then x_15 is a politician. There is at least one x_15 for which x_15 will make tea if and only if x_15 is poor. For all x_15, x_15 is poor. For all x_15, x_15 is a poet.
For all x_15, x_15 is a politician can be inferred via the universal modus ponens rule. For all x_15, x_15 is poor and x_15 is a poet can be inferred via the universal conjunction rule. For all x_15, x_15 is a poet and x_15 is poor can be inferred via the universal conjunction rule. There is at least one x_15 for which if x_15 makes tea, then x_15 is poor can be inferred via the existential biconditional elimination rule. There is at least one x_15 for which if x_15 were poor, then x_15 is making tea can be inferred via the existential biconditional elimination rule.