A、Because they can make many different kinds of masks. B、Because the city is a "sea of happiness" at that time. C、Because people

Venice, a small, waterside city in northeast Italy, boils with happiness and excitement once every year. Between February 21 and March 4, carnival hits the streets. For most people, carnival means many large parties and feasting. In Venice, it also means traditional masks and clothes.(26)These costumes were first meant to hide personal identities. Then, different social classes could mix in a sea of happiness.
    Today, people in Venice still dress up in the strangest ways—as armed soldiers, butchers and fishermen, for example. Bars and cafes are filled with partygoers who come to show off their beautiful clothes. Their designs and creations are made by special studios. Ready-made costumes are not acceptable. " In the months before the carnival we work overtime to meet the demand," said a mask-maker. " Many kilometers of silk and lace are made into costumes.(27)For shopkeepers, carnival is the best time of year. " At that time, the city was one of the wealthiest in Europe.
    The tradition of celebrating with masks and costumes is thought to have been started by the "Stocking Companies". These were groups of young men who organized parties and festivals and wore colorful stockings to distinguish themselves from other people. By the 18th century, the carnival had reached its top.(29)It all came to an end when Napoleon controlled Venice in 1797. But in 1979, local people brought the old traditions back to life.
    Now the Venice carnival attracts huge crowds from all over the world. The city certainly benefits—a whole industry has been built up around the carnival’s masks and clothes.
26. What are traditional costumes first used to do in the carnival?
27. Why do the shopkeepers like the carnival time?
28. Who started the tradition of wearing masks and costumes?
29. When did the carnival in Venice come to an end?