Option 3: Commercialization of Indian agriculture was one of the significant results of British rule in India in the 19th century.

During the British colonial period, India`s economy was transformed from a subsistence-based agriculture economy to a market-oriented agricultural economy. The British implemented various policies to enhance the production of raw materials and increase exports, and agriculture was a significant contributor to this process. They encouraged the production of commercial crops such as cotton, jute, and indigo, which had a ready market in Britain. This led to the commercialization of agriculture, with a shift away from subsistence farming towards cash crops.

The British also introduced new systems of land revenue collection, such as the Permanent Settlement of Bengal, which led to the commercialization of agriculture. Under this system, the British imposed a fixed land revenue tax on landowners, who were given permanent rights over their land in exchange. This encouraged landowners to cultivate cash crops instead of subsistence crops, as they could make more profits. This led to a decline in food crops and a significant increase in the production of commercial crops.

Additionally, the British built infrastructure such as railroads, canals, and ports to facilitate the transportation of agricultural goods from rural areas to urban centers and ports for export. This led to the growth of urban centers and the emergence of new market towns, creating new opportunities for trade and commerce.

Overall, the commercialization of agriculture led to the integration of Indian agriculture into the world economy, and India became a significant exporter of agricultural goods during the British colonial period. However, this also had negative consequences, such as the loss of food security and famine, as farmers switched from food crops to cash crops.

Therefore, the correct option for the question is Option 3: commercialization of Indian agriculture.