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: Mary is making tea if and only if Linda is a poet. If Mary makes tea, then Barbara is excited. For all z_2, z_2 is not excited.
If Mary makes tea, then Linda is a poet can be inferred via the biconditional elimination rule. If Linda were a poet, then Mary is making tea can be inferred via the biconditional elimination rule.