Explanation: The Ramganga is a significant tributary of the Ganga River, playing a crucial role in the hydrology and ecology of the region. It originates from the Doodhatoli ranges in the Pouri Gharhwal district of Uttarakhand. The Doodhatoli ranges are part of the larger Himalayan mountain system, which is the source of many important rivers in India.
The Ramganga flows through the state of Uttarakhand, passing through several districts before it reaches the border with Uttar Pradesh. In Uttar Pradesh, it continues its course and eventually joins the Ganga near Farrukhabad. This confluence is an important geographical feature, as it significantly increases the water volume of the Ganga, contributing to the river's ecological and agricultural importance downstream.
Understanding the geography of Uttarakhand and the river systems within the state is essential for comprehending the region's natural resources and environmental management. The Ramganga, along with other tributaries like the Alaknanda and Bhagirathi, which also originate in Uttarakhand, are vital for the Ganga's water supply and the ecological health of the river basin.
The other options provided in the question are also tributaries of the Ganga but originate from different locations and join the Ganga at different points. The Gomti, for example, originates from the Gomat Taal in Uttar Pradesh and joins the Ganga near Kaithi in Varanasi district. The Kali or Sarda originates from the Milam glacier in Uttarakhand but flows through Nepal before joining the Ganga in Bihar. The Gandak originates from the Himalayas in Nepal and joins the Ganga in Bihar.
In summary, the Ramganga is the correct answer because it is the only tributary that originates from the Doodhatoli ranges in Pouri Gharhwal district, Uttarakhand, and joins the Ganga near Farrukhabad in Uttar Pradesh. This geographical detail is crucial for understanding the river systems and the ecological significance of the region.