Please answer the following question: I'm taking a test and have to guess the right answer to the question after the article. Article: Venice is a city of the sea. It is built on islands which are in the middle of lagoon . Today, the city covers 118 islands. These islands are connected by bridges. There are about 400 bridges which cross 150 canals . It is difficult to forget the sea when you are in the city. Many people of Venice have always been fishermen, because the lagoon is full of fish. They also build ships, and travel to Dalmatia and Greece. Venice is the "Queen " of the Adriatic Sea. Every month thousands of people visit the city, which is very beautiful. But Venice is going down. It is going down and the water is going up. In 2040 Venice will be under water. The Adriatic will cover the city. The Venetians love their city and they want to stay there. They want to save Venice. They do not want to leave. How can they succeed ? They can put some big gates in the sea, which will close, so Venice will not go down. Question: The main differences between Venice and most other cities in the world is that _ . Options: A: Venice is bigger B: every year thousands of people visit Venice C: Venice is a very beautiful city D: Venice is a city of the sea
A:
D