The fastest growing country in South Asia is () A. China B. India C. Thailand D. Singapore.

South Asia is a developing country. After World War II, industries developed rapidly, mainly traditional light industries such as textiles and food. India is the fastest growing country in South Asia. After India's independence, on the basis of developing heavy industry with coal and iron resources, emerging industries such as electronics, automobile manufacturing, atomic energy and aerospace have gradually emerged. In recent years, the computer software industry in India has occupied an important position in the world.

Therefore, choose: B.