Read the passage and choose the correct answer A, B, C, or D for questions 21–25.
Urban growth has transformed cities into centers of innovation and economic development. As urban populations expand, city planners face the challenge of providing adequate infrastructure while minimizing environmental damage. One effective solution is the development of public transportation systems, which reduce traffic congestion and air pollution. Efficient buses, subways, and bike lanes help cities become more sustainable.
Another important aspect of sustainable cities is energy efficiency. Modern buildings are designed to consume less energy by using better insulation and smart technology. In addition, many cities encourage residents to reduce waste through recycling programs. These efforts not only protect the environment but also improve the quality of life for urban residents. Balancing development with sustainability is essential for the future of cities