Among the Mangaia People of Polynesia, Both Girls and Boys

Among the Mangaia people of Polynesia, both girls and boys are expected to have a high level of sexual desire in early adolescence. In contrast to the Mangaia, the Dani of New Guinea show little interest in sex beyond what is needed for reproduction. This illustrates:

A) that sex is social.
B) the intersex nature of sex.
C) that the age at menarche is increasing.
D) that biology has no role in sex.
E) that sex is biological.