The correct answer is: a) Canals and tubewells.
Canals and tubewells are the primary sources of irrigation in Bihar. Canals are artificial waterways that are used to transport water from a source, such as a river or lake, to a destination, such as a field or farm. Tubewells are vertical wells that are drilled into the ground to extract groundwater.
Canals and tubewells are both important sources of irrigation in Bihar because they provide a reliable source of water for crops. Canals are particularly important in areas where there is a lot of rainfall, as they can help to distribute the water evenly and prevent flooding. Tubewells are important in areas where there is less rainfall, as they can provide a source of water even during dry periods.
In addition to canals and tubewells, other sources of irrigation in Bihar include rivers and lakes, tanks and ponds, and drip irrigation and sprinklers. Rivers and lakes are natural sources of water that can be used for irrigation. Tanks and ponds are man-made reservoirs that can also be used for irrigation. Drip irrigation and sprinklers are methods of irrigation that use less water than traditional methods, such as canals and tubewells.
Drip irrigation is a method of irrigation in which water is delivered directly to the roots of plants through a network of small pipes. Sprinkler irrigation is a method of irrigation in which water is sprayed onto crops from above. Both drip irrigation and sprinkler irrigation can be used to save water and improve crop yields.
However, canals and tubewells are still the primary sources of irrigation in Bihar because they are more efficient and cost-effective than other methods.