▲ 閱讀下文，回答第 46−50 題
      An illusionist is a type of magician who appears to perform surprising, spectacular, andsometimes dangerous tricks. When watching such attractive and mysterious magic shows, theaudience usually asks the question, “How did they do that?” Here are several tricks for whichthese magicians have become famous around the world.
     Harry Houdini, noted for his magnificent escape acts, was actually an expert at handcuffs.With his hands handcuffed and chained, he would often jump into rivers long enough to createsuspense in the audience. Then, to everyone’s surprise, he would spring up, waving the chainsover his head, with his hands free. David Copperfield, a well-known stage magician, onceperformed a trick called “Walking Through the Great Wall of China” in front of a live audience.In this show, he seemed to have entered the Great Wall of China from one side and come out theother side. His other famous tricks were making New York’s Statue of Liberty disappear andflying over the Grand Canyon. Another magician, David Blaine, has done quite a few amazingendurance stunts over the course of his career. He was buried alive for a week, kept in a hollowcase of ice for 60 hours, and even stayed in a clear plastic box without any food at all for 44 days.
     Are you curious about how these illusionists have achieved their illusions? Maybe youneed to enter this secretive circle to find out how to do these puzzling tricks yourself.
46. What is the main idea of this passage?
(A) It is about the story of how to train magicians.
(B) It is about the personal life of three magicians.
(C) It is about the achievements of three magicians.
(D) It is about the solutions to all kinds of magic tricks.