The correct answer is: Rivers and reservoirs.
Rivers and reservoirs are the major source of irrigation in Chhattisgarh. The state has a number of rivers, including the Mahanadi, the Godavari, and the Indravati. These rivers are used to irrigate crops through a system of canals and dams.
Groundwater is also used for irrigation in Chhattisgarh, but it is not as reliable as rivers and reservoirs. Groundwater can be depleted, and it can also be contaminated.
Seawater desalination is not a major source of irrigation in Chhattisgarh. The process of desalination is expensive, and it requires a lot of energy.
Importing water from neighboring states is not a major source of irrigation in Chhattisgarh. The state is located in a relatively dry region, and it is not possible to import water from neighboring states.
In conclusion, the major source of irrigation in Chhattisgarh is rivers and reservoirs.