Which river in India is known as the 'Ruhr of India' for its industrial importance?

Option A (“Ganga”) is incorrect because it does not match the river basin, lake type, location, tributary relationship, project or hydrological feature specified in the question. Option C (“Brahmaputra”) is incorrect because it does not match the river basin, lake type, location, tributary relationship, project or hydrological feature specified in the question. Option D (“Mahanadi”) is incorrect because it does not match the river basin, lake type, location, tributary relationship, project or hydrological feature specified in the question. The key concept is to match the water body with its basin, type, location and defining feature. Therefore the correct option, index and explanation consistently identify Damodar. The Damodar River was historically called the 'Sorrow of Bengal' due to devastating floods. It was also called the 'Ruhr of India' because of the heavy industrialization along its banks (Jharkhand and West Bengal) - coal mines, steel plants, power plants. The Damodar Valley Corporation (DVC) was set up in 1948 modeled on the Tennessee Valley Authority (TVA) of USA.