The correct answer is Suryavarman II.

Angkor Wat, a magnificent example of Khmer architecture and a UNESCO World Heritage site, was primarily constructed during the reign of King Suryavarman II (reigned c. 1113 – 1150 CE). He oversaw the temple's extensive building program, transforming it from a smaller structure into the awe-inspiring monument we see today. While previous Khmer rulers made contributions to the Angkor temple complex, Suryavarman II is unequivocally credited with the grand scale vision and execution of Angkor Wat as the state temple of his empire. The temple's design, layout, and intricate carvings reflect the sophisticated religious and political ideology of his reign. The impressive scale and artistic achievement of Angkor Wat under Suryavarman II solidified his legacy as one of the most significant figures in Khmer history. His reign marked a high point in Khmer power and artistic accomplishment, leaving an enduring mark on Cambodian culture and global heritage. The meticulous craftsmanship and the vast scale of the construction project showcase the advanced engineering and organizational abilities of the Khmer empire under Suryavarman II. The religious significance of Angkor Wat, dedicated to the Hindu god Vishnu, further reinforces Suryavarman II's central role in the temple's creation and the cultural and spiritual life of the Khmer people.