India was able to prosper because of the Silk Road. Option A is correct.
The Silk Road referes to an ancient network of trade routes that linked the East and West. It was key to cultural exchange between the regions for many centuries. The Silk Road is the terrestrial routes linking East Asia and Southeast Asia with East Africa, West Asia and Southern Europe.
Trade on the Road resulted in the development of some civilizations including China, Korea, Japan, the Indian subcontinent, Iran/Persia, Europe, the Horn of Africa and Arabia.