When the Authors Emphasize That, When a Child Gets a Pair

When the authors emphasize that, when a child gets a pair of gender binary glasses, it's just their first pair, they mean to say that

A) parents are the primary sources of information showing children that gender matters.
B) children can't see gender at all until they are actively taught to follow the gender rules of their culture.
C) adults expect even very young children to follow rigid gender binary rules.
D) young children perceive gender in their society but differently than they may when they are adults.