**Agriculture is the main occupation of the people living in the area of Ganga-Brahmaputra basin where flat land is available to grow crops.**

The Ganga-Brahmaputra basin is one of the largest river basins in the world, covering parts of India, Bangladesh, Nepal, Bhutan, and Tibet. The basin is known for its fertile alluvial plains, which are formed by the sediment deposits brought by the rivers. These plains offer flat land that is suitable for agriculture.

**Importance of Agriculture in the Ganga-Brahmaputra Basin:**

1. **Food Production:** Agriculture is the primary source of food production in the region. The flat land in the basin allows for the cultivation of a variety of crops such as rice, wheat, pulses, oilseeds, and vegetables. These crops not only meet the local food requirements but are also exported to other regions.

2. **Livelihoods:** Agriculture provides livelihoods to a large portion of the population in the Ganga-Brahmaputra basin. Farmers engage in various agricultural activities such as crop cultivation, animal husbandry, and fisheries. These activities provide employment opportunities and income for the local communities.

3. **Economic Contribution:** Agriculture contributes significantly to the economy of the region. The agricultural produce from the basin is not only consumed locally but also sold in markets, generating income for farmers and the local economy. It also supports related industries such as food processing and agro-based industries.

4. **Cultural Significance:** Agriculture has a deep cultural significance in the region. The Ganga-Brahmaputra basin has a rich agricultural heritage, with traditional farming practices being passed down through generations. The festivals and rituals in the region often revolve around agriculture, highlighting its importance in the local culture.

5. **Sustainable Resource Management:** Agriculture in the Ganga-Brahmaputra basin is closely linked to the management of natural resources. Farmers practice sustainable agriculture techniques such as crop rotation, organic farming, and water conservation to ensure the long-term productivity of the land. This helps in preserving the ecological balance of the region.

In conclusion, agriculture is the main occupation of the people living in the area of the Ganga-Brahmaputra basin where flat land is available to grow crops. It not only provides food and livelihoods but also contributes to the economy and cultural fabric of the region.

(Correct Option: C, Agriculture)

The Ganga-Brahmaputra basin is formed in the Indian subcontinent by the tributaries of the rivers Ganga and Brahmaputra.

The basin area has varied topography. The
environment plays a dominant role in the distribution
of the population. The mountain areas with steep slopes have inhospitable terrain. Therefore less number of people live in the mountain area of the Ganga-Brahmaputra basin. The plain area provides the most suitable land for human habitation. The soil is fertile. Agriculture is the main occupation of the people where flat land is available to grow crops. The density of population of the plains is very high. The main crop is paddy. Since cultivation of paddy requires sufficient water, it is grown in the areas where the amount of rainfall is high.