Which one of the following is not a tributary of the river Ganga?

The Ganga river system is the largest in India, comprising numerous Himalayan and Peninsular tributaries. The Son is a major right-bank tributary originating from the Peninsular uplands [1]. The Mahananda and Sharada (also known as Sarda or Kali) are significant left-bank tributaries of the Ganga [2]. Specifically, the Sharada river demarcates the western border between India and Nepal before joining the Ghaghara, a major Ganga tributary. In contrast, the Teesta river is not a tributary of the Ganga; it is a major trans-boundary river that flows through Sikkim and West Bengal before joining the Brahmaputra river in Bangladesh. While the Teesta is a subject of water-sharing discussions between India and Bangladesh, it remains part of the Brahmaputra (Jamuna) drainage system rather than the Ganges system.

Sources

1. [1] INDIA PHYSICAL ENVIRONMENT, Geography Class XI (NCERT 2025 ed.) > Chapter 3: Drainage System > Do you Know? > p. 22
2. [2] Geography of India ,Majid Husain, (McGrawHill 9th ed.) > Chapter 4: Climate of India > 1. The Ganga River Basin > p. 47