The biggest source of irrigation in U.P. is

Canal
Pond
Tubewell
Well

The correct answer is (c). Tubewells are the biggest source of irrigation in Uttar Pradesh, accounting for over 60% of the total irrigation. Canals are the second largest source, followed by wells and ponds.

Tubewells are a type of well that is used to extract groundwater. They are typically powered by electricity or diesel engines, and can be used to irrigate crops, provide drinking water, and generate electricity.

Canals are artificial waterways that are used to transport water from one place to another. They are typically built to irrigate crops, but can also be used for transportation, flood control, and recreation.

Wells are holes that are dug into the ground to reach groundwater. They can be used to extract water for drinking, irrigation, or industrial purposes.

Ponds are small bodies of water that are typically formed by natural processes, such as rainfall or runoff. They can be used for irrigation, fish farming, recreation, and water storage.

In Uttar Pradesh, tubewells are the most efficient and reliable source of irrigation. They are also the most cost-effective option, as they do not require the construction of canals or other infrastructure. As a result, tubewells have become the dominant source of irrigation in the state.