The correct option is D Coal, cotton, rice, wheat, jute and iron are commodities which are included in Internal trade.
In 1951, when the first five year plan began, import of raw materials and industrial goods grew because of increased importance to production. India imported machines, iron, mineral oil, fertilisers, medicines, etc. After independence, there was also a rise in exports of goods from India, which helped gain from the foreign exchange. Internal trade happens when the goods are exported and imported within the political boundaries of a country, and the domestic currency is used for payment.