The correct answer is option 'A' - Indian Oil Corporation Ltd.

Indian Oil Corporation Ltd (IOCL) is a leading public sector oil company in India. It is responsible for the establishment of refineries in various locations across the country. Three of the prominent refineries set up by IOCL are Mathura, Digboi, and Panipat.

1. Mathura Refinery:
- The Mathura Refinery is located in Mathura, Uttar Pradesh. It was commissioned in 1982.
- It has a crude oil processing capacity of 8 million metric tonnes per annum (MMTPA).
- The refinery produces a wide range of petroleum products, including LPG, motor spirit, high-speed diesel, aviation turbine fuel, and bitumen.

2. Digboi Refinery:
- The Digboi Refinery is the oldest operating refinery in India and is located in Digboi, Assam.
- It was commissioned in 1901 and has a processing capacity of 0.65 MMTPA.
- The refinery is known for its production of high-quality lubricants and waxes.

3. Panipat Refinery:
- The Panipat Refinery is situated in Panipat, Haryana. It is one of the largest and most complex refineries in India.
- It was commissioned in 1998 and has a processing capacity of 15 MMTPA.
- The refinery produces various petroleum products, including gasoline, diesel, aviation turbine fuel, liquefied petroleum gas, and petrochemical feedstock.

IOCL is responsible for the setting up and operating these refineries to meet the growing demand for petroleum products in India. These refineries play a crucial role in the country's energy sector by processing crude oil into various products that are essential for transportation, industrial, and domestic purposes.

In addition to Mathura, Digboi, and Panipat, IOCL also operates several other refineries across India, including refineries in Gujarat, Odisha, Bihar, and Tamil Nadu. These refineries contribute significantly to the country's energy security and help in meeting the fuel requirements of various sectors, including transportation, agriculture, and manufacturing.

Overall, IOCL, as a leading oil company in India, plays a vital role in ensuring the availability of petroleum products and meeting the energy needs of the nation, with Mathura, Digboi, and Panipat refineries being an integral part of its operations.