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_8, if x_8 were a mechanic, then x_8 is not driving a car. For all x_8, x_8 will climb a mountain if and only if x_8 is rich. For all x_8, x_8 is not rich. For all x_8, x_8 will climb a mountain or x_8 will drive a car.
For all x_8, if x_8 climbs a mountain, then x_8 is rich can be inferred via the universal biconditional elimination rule. For all x_8, if x_8 were rich, then x_8 is climbing a mountain can be inferred via the universal biconditional elimination rule. For all x_8, x_8 will not climb a mountain can be inferred via the universal biconditional elimination rule.