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 will not climb a mountain. For all x_6, if x_6 were a poet, then x_6 is climbing a mountain. For all x_6, x_6 is a poet if and only if x_6 is a police officer. For all x_6, if x_6 were a poet, then x_6 is a police officer.
For all x_6, x_6 is not a poet can be inferred via the universal modus tollens rule. For all x_6, if x_6 were a poet, then x_6 is a police officer can be inferred via the universal biconditional elimination rule. For all x_6, if x_6 were a police officer, then x_6 is a poet can be inferred via the universal biconditional elimination rule.