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 y, y will climb a mountain if and only if y is a bartender. There is at least one y for which if y climbs a mountain, then y is a bartender. For all y, if y drives a car, then y is a bartender.
For all y, if y climbs a mountain, then y is a bartender can be inferred via the universal biconditional elimination rule. For all y, if y were a bartender, then y is climbing a mountain can be inferred via the universal biconditional elimination rule.