Read the following article and answer the question. Article: What do you do in a situation like this? You're calling dinner with friends at a nice restaurant. You're having a great time when a phone rings at the table next to you. A man takes out his phone and starts talking loudly about problems he's having with his girlfriend. He talks for almost ten minutes! This happens all the time-on buses, in restaurants, everywhere! Many people find cell phones useful in their daily lives. But we've all sat next to someone talking too loudly on a cell phone. You may want to tell the loudmouth to end the conversation, but let the management take care of those noisy customers. You can only control your own behavior. Here are a few rules: Off means off! Follow the rules of restaurants and other public places . If a sign says "turn off cell phones", don't use your phone. If you are allowed, speak softly and for a short time and try to move away form other people. Lights off, phone off! Never make calls in a theater or at the movies. Pay attention! Talking on a cell phone while driving is dangerous. And watch where you're going when you're walking down the streets and talking on the phone. As more people use cell phones, things are only going to get worse. So, the next time you're getting ready to make a call, stop and consider the people around you. Question: From the passage we can infer that _ . Answer:

Choices:
[A]. cell phones have become the most useful tool in our life;
[B]. public manners play an important role in our life;
[C]. cell phones lead to people's bad relationship;
[D]. people ought to turn cell phones off in a public places;
Answer:
[B].