Concept:The Chola king who supported the Sailendra ruler of Sri Vijaya in building a Buddhist monastery at Nagapattinam was Rajaraja I.
Explanation:During the reign of Rajaraja I (985–1014 CE), the Sailendra king Sri Mara Vijayottungavarman of Sri Vijaya sought permission to construct a Buddhist Vihara at Nagapattinam (then called Negapatnam).
Rajaraja I granted this request as a strategic diplomatic move to maintain friendly relations with the powerful maritime kingdom of Sri Vijaya.
This vihara, known as the Sailendra Vihara, became an important centre for Buddhist learning under Chola patronage.
The other options are incorrect:
• Parantaka I is known for his military campaigns and administrative reforms, but he had no recorded connection with building a Buddhist vihara at Nagapattinam.
• Rajendra I, though famous for his naval expedition that conquered parts of Sri Vijaya, did not commission such a vihara.
• Kulottunga I is remembered for his governance and temple-building activities, not for this specific monastery.
Thus, Rajaraja I's patronage of the Sailendra ruler demonstrates his shrewd diplomatic strategy in Southeast Asian affairs.
Answer:Rajaraja I