阅读下面一篇短文，掌握其大意，从题中所给的A、B、C三个选项中，选出可以填入相应空白处的最佳答案。

    How much time do you spend in front of a screen every day? If your answer is about one hour.

    Then maybe you are one of the1teenagers in the world.

    Scientists did a2.They asked students aged 13 to 18 how long it3them to have fun on phones and computers. They also asked about4feelings of happiness. They found that those who spend more time on their smart phones are unhappier. "Spend no more than two hours a day on digital media(电子产品), 5try to spend more time with friends and on exercise. These two activities bring greater happiness." Jean Twenge, the scientist who led the study, said.