The correct option is Goriganga.
Explanation
The Sarda River (also known as Saryu) is a significant trans-boundary river in the Himalayan drainage system. It is a tributary of the Ghaghara River, which eventually flows into the Ganga.
Detailed Analysis:
- The river rises in the Milam glacier in the Nepal Himalayas.
- At its specific point of origin and in the upper reaches, it is known as the Goriganga.
- As it flows downstream, it forms the boundary between Nepal and the Kumaon region of India, where it is referred to as the Kali or Chauk.
- It eventually joins the Ghaghara River.
Analysis of Incorrect Options:
- Kaligandak Kaligandak: This river is part of the Gandak system and originates between Dhaulagiri and Mount Everest in Nepal.
- Trishulganga Trishulganga: This is a major tributary of the Gandak River in central Nepal.
- Karnali Karnali: This is the name of the Ghaghara River itself in Nepal. The Sarda is a tributary that flows into the Ghaghara (Karnali).
Key Takeaway: The Sarda River originates as the Goriganga from the Milam glacier and is subsequently known as the Kali along the Indo-Nepal border.