The Mekong River, which flows through Vietnam via the Mekong Delta, empties into which sea?

The correct answer is the South China Sea, which Vietnam officially refers to as the East Sea. The Mekong River originates on the Tibetan Plateau and flows roughly 4,350 kilometres through China, Myanmar, Laos, Thailand, Cambodia and finally Vietnam, where it fans out into the Mekong Delta, a low-lying network of distributaries in southern Vietnam, before draining into the South China Sea, a fact consistent with the CIA World Factbook's description of Vietnam's hydrography. The Mekong Delta is one of the most agriculturally productive regions in the world and is often called Vietnam's rice bowl because its fertile silt deposits support intensive rice cultivation and aquaculture that feed both domestic consumption and significant export volumes. The Gulf of Thailand (option A) is incorrect; while it lies close to the Mekong Delta's southwestern edge and receives some smaller Vietnamese waterways, the Mekong's main distributary channels empty eastward into the South China Sea, not into this gulf. The Andaman Sea (option B) is incorrect because it lies far to the west, off the coasts of Myanmar and Thailand, entirely disconnected from the Mekong's outflow. The Bay of Bengal (option D) is incorrect for the same reason; it lies on the Indian Ocean side of the Indochinese peninsula, nowhere near Vietnam's eastern seaboard. A common exam confusion is mixing up the Gulf of Thailand with the South China Sea because both touch Southeast Asian coastlines, but the Mekong's main mouth is firmly on the South China Sea side. Revision takeaway: the Mekong flows through six countries and finally empties into the South China Sea via Vietnam's Mekong Delta, a sea Vietnam itself calls the East Sea in official and everyday usage.