Read the passage, and choose the correct answer A, B, C or D for each

Read the passage, and choose the correct answer A, B, C or D for each question.In the old days, Vietnamese roads were seen with bicycles and a few trucks. Now they are full of a variety of vehicles. The Vietnamese carry a huge load of a variety of goods up to over one hundred kilograms, especially during the war.Time has gone by and fewer bikes are visible in the street. In big cities, many people think that bicycles belong to the inferior classes and seem unfashionable. That is why people often find it hard - psychologically and physically - to park their bikes when going to a modern cafe or shopping malls. Motorbikes are the main mode of transport in Viet Nam, with 24 million of them in a country of 87 million people in 2009, one of the highest ratios in the world. More motorbikes of all brands have dominated the road. The mobility which motorbikes provide is so crucial to workers in big cities. Some youths try to show off with expensive motorbikes of famous brands. Almost anything can be transported on a motorcycle. The loads include baskets of fruits, tree trunks, live pigs, flocks of live ducks and stacked crates of raw eggs. Two thirds of Viet Nam's population of 85 million arc under 30, and the motorcycle has become the center of youth culture.Nowadays, bicycles .............