【正确答案】 C

【答案解析】本题为细节题。答案在第一段。由“…by the time they get to high school，they are victims of what the researchers call a major new gender(性别)gap in technology．"和“Girls tend to be less comfortable than boys with the computer．”可知C为正确选项。A和D为具体细节，是针对这一原因的进一步说明。而根据文章第一句“The girls in this sixth grade class in East Palo Alto，California，all have the same access to computers as boys．”可知是在六年级的时候女孩和男孩在计算机方面机会相同，而到高中以后就不是这样了，故B也可排除。