单选题：For many parents, raising a teenager is like fighting a long

For many parents, raising a teenager is like fighting a long war, but years go by without any clear winner. Like a border conflict between neighboring countries, the parent-teen war is about boundaries: Where is the line between what I control and what you do?
Both sides want peace, but neither feels it has any power to stop the conflict. In part, this is because neither is willing to admit any responsibility for starting it. From the parents' point of view ,the only cause of their fight is their adolescents' complete unreasonableness. And of course, the teens see it in exactly the same way, except oppositely. Both feet trapped.
In this article. I'll describe three no-win situations that commonly arise between teens and parents and then suggest some ways out of the trap. The first no - win situation is quarrels over unimportant things. Examples include the color of the teen's hair, the cleanliness of the bedroom, the preferred style of clothing, the child's failure to eat a good breakfast before school, or his tendency to sleep until noon on the weekends. Second, blaming. The goal of a blaming battle is to make the other admit that his bad attitude is the reason why everything goes wrong. Third, needing to be right, it doesn't matter what the topic is politics, the laws of physics, or the proper way to break an egg--the point of these arguments is to prove that you are right and the other person is wrong, for both wish to be considered an authority someone who actually knows something and therefore to command respect. Unfortunately, as long as parents and teens continue to assume that they know more than the other, they'll continue to fight these battles forever and never make any real progress.
Why does the author compare the parent-teen war to a border conflict? A．Because both can continue for generations.
B．Because both are about where to draw the line.
C．Because neither has any clear winner.
D．Because neither can be put to an end.