context: Hoi An is located in central Vietnam, in the northeastern part of the province of Quangnam, at the mouth of the Thubon River, approximately 50 north of the city of Tamky and 30 south of Da Nang. The main part of the city is located on the northern bank of the river, at its confluence with the South China sea. Administratively, the city also includes several islands at the mouth of the Thubon River and the Tyam Islands, located near the coast. Due to sediment in the Hoi An area, various channel processes continue, including the formation of sandbanks and lagoons, and changes in the river and sea coastlines [2] [37] [38] [39].
question: Which sea is Hoian located on?
answers.text: South China