The magnificent Brihadeeswarar Temple in Thanjavur was built during the reign of:

Rajaraja Chola I
Rajendra Chola I
Kulothunga Chola I
Vikrama Chola

The correct answer is: a) Rajaraja Chola I.

The Brihadeeswarar Temple, also known as Rajarajeswaram Temple, is a Hindu temple dedicated to Shiva located in Thanjavur, Tamil Nadu, India. It was built by the Chola king Rajaraja Chola I in the 11th century CE. The temple is one of the largest and most impressive Hindu temples in the world. It is a UNESCO World Heritage Site.

The temple is built in the Dravidian style of architecture. It is a large complex with a number of different structures, including the main shrine, the mandapa (hall), and the gopuram (gateway). The main shrine is dedicated to Shiva and is the largest in the world. It is a 13-tiered vimana (tower) that is 66 meters (217 feet) tall. The mandapa is a large hall that is used for religious ceremonies. It is decorated with sculptures of gods and goddesses. The gopuram is a gateway that leads to the temple complex. It is a 16-tiered tower that is 58 meters (190 feet) tall.

The Brihadeeswarar Temple is a masterpiece of Hindu architecture. It is a UNESCO World Heritage Site and is one of the most popular tourist destinations in India.

Option b) Rajendra Chola I is incorrect because he was the son of Rajaraja Chola I and succeeded him to the throne. He did not build the Brihadeeswarar Temple.

Option c) Kulothunga Chola I is incorrect because he was the grandson of Rajaraja Chola I and ruled after Rajendra Chola I. He did not build the Brihadeeswarar Temple.

Option d) Vikrama Chola is incorrect because he was the great-grandson of Rajaraja Chola I and ruled after Kulothunga Chola I. He did not build the Brihadeeswarar Temple.