What Explains Why African-American Children in the United States Tend

What explains why African-American children in the United States tend to adopt less stereotyped views of the sexes in comparison to their peers?

A) Their fathers are much harsher than father in European-American homes.
B) They are more likely to be raised by a single mother who displays both instrumental and expressive characteristics.
C) Their mothers are overly nurturing.
D) They tend to be raised in a nuclear family and have strong exposure to both gender roles.