Where does the river Brahmaputra originate?

The correct answer is Option (2) → Lake Mansarovar

The Brahmaputra rises in the Chemayungdung glacier of the Kailash range, near Lake Mansarovar in Tibet, which is why Mansarovar is named as its source. It flows east across Tibet as the Tsangpo, turns south round the peak of Namcha Barwa and enters India in Arunachal Pradesh, where it is called the Siang or Dihang.