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_2, if x_2 were fast, then x_2 is not climbing a mountain. There is at least one x_2 for which if x_2 were poor, then x_2 is fast. For all x_2, x_2 will climb a mountain.
For all x_2, x_2 is not fast can be inferred via the universal modus tollens rule.