article: Have you ever tried scuba-diving ? It is a very wonderful experience. _ is a kind of machine which can help people breathe under the water for a long time. The machine is invented by Jacques Cousteau and his friend.
  Cousteau, a French man, is full of new ideas. Since he was a child, he has dreamed of diving   deep to see the wonderful world under the sea. Later with the help of the scuba machine, his dream was realized. Cousteau took lots of pictures and videos of many strange things that people had never seen before. He spent eight years making a TV show named The Undersea World of Jacques Cousteau. People were surprised at so many beautiful things under the water.
  Cousteau loved the coral reels  and the colorful fish very much. However, he was sad to see that the beautiful coral reels were dead and grey when he returned some years later. He tried his best to encourage people not to pollute our seas and oceans any more.
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question: It took Cousteau  _  years to make the TV show, The Undersea World of Jacques Cousteau.
options: 4 6 8 10