article: It is December 25th, 2050. The people in the city are all celebrating Christmas. I'm the mayor of our city. My citizens and I are holding a big party under the sea, though you wouldn't believe it. But please do not feel excited, you should feel sad because we have to live under the sea. Because of the pollution, the earth has been completely destroyed, from top to bottom. The atmosphere has no oxygen and moisture. As a result, the plants are burned by the strong sunlight with a great number of harmful rays. Of course, none of them are still alive. Not only no green, but also the temperature reaches about 121degC all day even in winter because there is too much CO2 circling the earth.
  On the land, there is no life. Luckily, the sea is not destroyed by human. So, we have to move into the sea. At the bottom of the water, people have built many new cities. There is a lot of advanced(,) equipment in each city. Computers are used to control all the machines, even the people's life. We can also make the seawater into fresh water. There are two machines making oxygen. If they stop working for only one minute, more than 10 million people will die.
  The population of our city is over 30 million and, of course, it is quite crowded. We have lots of high buildings and bridges. The roads are wide, too. Our cars are small UFOs, don't be surprised, it is true. At the bottom of the sea you can't see anything, because there is no light all day. However, we have advanced lighting equipment so that we can see the "sun" under the sea. Of course, the advanced lighting equipment is very expensive. And if it doesn't work, we can see nothing under the sea. What should we do then?
question: . The best title for this passage might be   _   .
options: A Christmas In The Future A City Under The Sea The Underwater Life The Future Life Under The Sea