Answer the following question: I'm taking a test and have to guess the right answer to the question after the article. Article: People believe that climbing can do good to health. Where can you learn the skill of climbing then? If you think that you have to go to the mountains to learn how to climb,you're wrong. Many Americans are learning to climb in city gyms . Here,people are learning on special climbing walls. The climbing wall goes straight up and has small holding places for hands and feet. How do people climb the wall? To climb,you need special shoes and a harness around your chest to hold you. There are ropes tied to your harness. The ropes hold you in place so that you don't fall. A beginner's wall is usually about 15 feet high,and you climb straight up. There are small pieces of metal that stick out for you to stand on and hold on to. Sometimes it's easy to see the new piece of metal. Sometimes, it's not. The most difficult part is to control your fear. It's normal for humans to be afraid of falling, so it's difficult not to feel fear. But when you move away from the wall,the harness and the ropes hold you,and you begin to feel safe. You move slowly until you reach the top. Climbing attracts people because it's good exercise for almost everyone. You use your whole body,especially your arms and legs. This sport gives your body a complete _ . When you climb,both your mind and your body can become stronger. Question: Why does the author write this passage? Options: A: To tell people where to find gyms. B: To prove the basic need for climbing. C: To encourage people to climb mountains. D: To introduce the sport of wall climbing.
Answer:
D