Rules for last-pair

Define rules to implement the last-pair operation of exercise 2.17 , which returns a list containing the last element of a nonempty list. Check your rules on queries such as (last-pair (3) ?x), (last-pair (1 2 3) ?x), and (last-pair (2 ?x) (3)). Do your rules work correctly on queries such as (last-pair ?x (3)) ?