Please answer the following question: Read the following article and select the best answer. Article: SHANGHAI - Health experts in Shanghai are calling for more protection for young children as the latest research shows about half of the youngsters are suffering from secondhand smoke. About 45 percent of children suffer passive smoking in families, 50 percent in public places, and almost 6 percent on public transportation, shows a research released by the Shanghai Children's Medical Center on Tuesday. "Not only adults but also children and newborn babies are at risk for the adverse effects of passive smoking," said Tang Jingyan, a doctor at the Shanghai Children's Medical Center. "Actually, those young children whose bodies are still growing and developing are more sensitive to the effects of secondhand smoke." Research has shown that children who are exposed to secondhand smoke will suffer from more colds, coughs and sore throats, and they are more likely to suffer from bronchitis, pneumonia and will have a higher risk of developing cancer. Doctors even suggested that children suffering passive smoking are more likely to have behavioral problems and may not develop mentally as quickly as their peers. Other research by the Shanghai Children's Medical Center has found that more than 80 percent of child patients in the center live in a smoke-filled household, where one or both parents smoke. "Though doctors have stressed the harm of passive smoking over and over, it is still hard to reach a totally 'smoke free' home," said a pediatrician named Zhang Yiwen, noting that parents are often tempted to smoke even though they have learned the harmful effects of secondhand smoke. China has 540 million people suffering from passive smoke, 180 million of them younger than 15.The age of smokers is also getting lower, earlier reports said. "There are more young smokers than before.You can see young people wearing a school uniform and carrying a schoolbag light a cigarette on the street.Some of them are even female students," said Jing Xingming, a professor of children's developmental behavior at the center. "Children like... Question: What is the main idea of the passage? - About half of the youngsters are suffering from secondhand smoke. - Experts are calling for more protection for youngsters from smoking. - More and more youngsters are picking up the habit of smoking. - Smoking does great harm to the health of the youngsters.
Answer:
Experts are calling for more protection for youngsters from smoking.