It is a phrase that is commonly said and it doesn’t compare any two things, so it is an idiom.
Answer:
The name Hopi is a shortened form of their autonym, Hopituh Shi-nu-mu ("The Peaceful People" or "Peaceful Little Ones").
Definition of Hopi: A member of a Pueblo people living chiefly in northeastern Arizona.
The best of all possible manners within the best if all possible worlds.
The answer is D. Remain.
Happy Studying! ^=^