During Their Exploration of Mars, American Scientists Discover What They

During their exploration of Mars, American scientists discover what they label a "stone age" society of humans living in caves just under the surface. The people, who are peace loving and welcoming toward the visitors from earth, have no written language or organized religion. Also, they do not have weapons or a concept of war. Which of the following assessments would a social Darwinist most likely make regarding the morality of this society?

A) They are clearly more morally advanced than earth's culture because they are trusting and nonviolent.
B) They are clearly morally inferior to earth's cultures because their culture is primitive and lacks both technology and a belief in God.
C) Because culture is the source of morality, their culture cannot be judged as either morally superior or morally inferior to earth's cultures, but simply as different.
D) Because morality is a meaningless concept, this question is also meaningless.