Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct option to each of the questions that follow.

     Denmark is one of the most bicycle-friendly countries in the world. Approximately 40 percent of the people in its capital, Copenhagen, commute to school or work by bicycle.

     Why are bikes so popular in Denmark? First of all, the government is worried about pollution. Cars pollute the air, and the number of cars is growing. Denmark imposes a very high tax on cars because the government wants more people to ride bikes instead. Another reason for the popularity of bicycles is that Denmark is a very flat country. The highest place in the country is only 557 feet (170 m), so it is a very easy place to ride a bike. Moreover, in Copenhagen, there are also special lanes just for cyclists. Cars must stop when a bike is crossing the road. Some places have special traffic lights to tell drivers that bikes are going to cross the road.

     About 20 percent of people in nearby towns commute to Copenhagen on their bikes. But Denmark wants to double this number. The government is planning to build bicycle "superhighways." These roads will only be for cyclists. Cyclists will have special places on these highways to stop and rest or put air in their tires. With these bicycle superhighways, Copenhagen may become the most bicycle-friendly city in the world. Many other cities, such as New York, London, and Guangzhou are thinking about copying this plan. In fact, there is a new word for making a city more bicycle-friendly - "Copenhagenization."

(Source: Select readings)

What is NOT the reason why bicycles are popular in Denmark?