Nowadays more and more young athletes are taking part in the risky activities called "extreme sports" or "X-sports". In the past young athletes would play baseball. Today, they want risk and excitement -- the closer to the edge, the better. They snowboard over cliff and hike deep mountains. Extreme sports started as an alternative to more expensive sports such as golf. A city kid who couldn't afford expensive sports equipment could get a skateboard and have fun. But now it has become a whole new area of sports, with specialized equipment and high levels of skill. There is even an Olympics for extreme sports, called the winter x-game, which includes snow mountain hiking and ice climbing. What makes extreme sports so popular? Maybe it's because people love the risk. City people want to be outdoors on the weekends and do something challenging. The new equipment is so much better that people can take more risks without getting hurt. Sure there's a risk. Once you go mountain hiking or snowboarding, it's impossible to go back to have riding or skiing. It's just too boring. Now even the older crowd is starting to join in. Every weekend, groups of friends in their early 30s get together. On weekdays they work as computer programmers in the same office. On weekends they hike mountains together. Extreme sports are certainly not for everyone. Most people still prefer to play basketball or watch sports on TV. But it has been a fact that extreme sports are gaining popularity. The main idea of this passage is   _  .
extreme sports are certainly not for everyone the benefits and costs of extreme sports the development of extreme sports what makes extreme sports so popular
Question: Nowadays more and more young athletes are taking part in the risky activities called "extreme sports" or "X-sports". In the past young athletes would play baseball. Today, they want risk and excitement -- the closer to the edge, the better. They snowboard over cliff and hike deep mountains. Extreme sports started as an alternative to more expensive sports such as golf. A city kid who couldn't afford expensive sports equipment could get a skateboard and have fun. But now it has become a whole new area of sports, with specialized equipment and high levels of skill. There is even an Olympics for extreme sports, called the winter x-game, which includes snow mountain hiking and ice climbing. What makes extreme sports so popular? Maybe it's because people love the risk. City people want to be outdoors on the weekends and do something challenging. The new equipment is so much better that people can take more risks without getting hurt. Sure there's a risk. Once you go mountain hiking or snowboarding, it's impossible to go back to have riding or skiing. It's just too boring. Now even the older crowd is starting to join in. Every weekend, groups of friends in their early 30s get together. On weekdays they work as computer programmers in the same office. On weekends they hike mountains together. Extreme sports are certainly not for everyone. Most people still prefer to play basketball or watch sports on TV. But it has been a fact that extreme sports are gaining popularity. The main idea of this passage is   _  .
A. extreme sports are certainly not for everyone
B. the benefits and costs of extreme sports
C. the development of extreme sports
D. what makes extreme sports so popular
Answer: