题目

    Are people less happy or happier when they get older? If your answer is“happier”，then you are right，based on a study published seven years ago．It found that people become happier and experience less worry after age fifty．In fact，it found that by the age of eighty-five，people are happier with their life than they were at eighteen．     The finding came from a Gallup survey of more than three hundred and forty thousand adults in the United States in 2008．At that time，people were between the ages of eighteen and eighty-five．     Arthur Stone in the DeWhen television was first introduced, the extent _______ it would affect society could not have been foreseen.A．of whichB．of whatC．to whichD．in which