Read the following article and select the best answer. Article: On Christmas Eve a few years ago an English couple received a very special telephone call. It was only a 20-second call but it was very important. The Haydens' 15-year-old daughter had disappeared six months before. On Christmas Eve she rang them. "I'm phoning to wish a happy Christmas," she said, "I love you." Ronals and Edwine Hayden were so happy that they started a special telephone service called "Alive and Well". The service helps parents to get in touch with children who have run away from home. Young people can phone "Alive and Well" and leave a message for their parents. The telephones are answered by answering machines. So no one can speak to the child of making him return home. Parents of runaway children who are under eighteen can ask the police to bring their children home, so children do not want to tell their parents where they are. Through "Alive and Well" they can telephone their parents without worrying about this or giving out their addresses. The Haydens and their helpers write down the tape recorded telephone messages and connect the address given. Many of the 30,000 British teenagers who have left home are probably in London. For only two pence they can go into a telephone coin box and call their parents. They can dial 5675339 and stop a parent's worry: Is he dead or alive? Question: Through "Alive and Well", parents of runaway children _ . - often fail to persuade their children to return home - know nothing from their children - can say nothing to their children - can ask the police to help them to find lost children
A:
can say nothing to their children