单项选择题

Questions 21-25 are based on the following passage:

I hear many parents complaining that their teenage children are rebelling. I wish it were so. At your age you ought to be growing away from your parents. You should be learning to stand on your own two feet. But take a good look at the present rebellion. It seems that teenagers are all taking the same way of showing that they disagree with their parents. Instead of striking out boldly on their own, most of them are clutching at one another’s hands for courage. They claim they want to dress as they please. But they all wear the same clothes. They set off in new directions in music. But somehow they all end up just by listening to the same record. Their reason for thinking or acting in this way is that the crowd is doing it. It has become harder and harder for a teenager to stand up against the popularity wave and to go his or her own way. Industry has firmly carved out a teenage market. These days every teenager can learn from the advertisements what a teenager should have and be. And many of today’s parents have come to award high marks for the popularity of their children. All this adds up to a greater barrier for the teenager who wants to find his or her own path. But the barrier is worth climbing over. The path is worth following. Find yourself. Be yourself. Popularity will come--with the people who respect you for whom you are. That’s the only kind of popularity that really counts.

The main purpose of this passage is to tell ______.