Explanation: The Ganga river, one of the most significant rivers in India, originates from the Gangotri Glacier in the Himalayas and flows through several states before reaching the Bay of Bengal. In West Bengal, the Ganga river reaches its easternmost point at Farraka, a town located in the Malda district. This location is crucial for several reasons:
1. **Geographical Significance**: Farraka is the point where the Ganga river splits into two major branches: the Hooghly and the Padma. The Hooghly flows through West Bengal and eventually meets the Bay of Bengal, while the Padma flows into Bangladesh.
2. **Farakka Barrage**: The Farakka Barrage, constructed in 1975, is a major water diversion project located at Farraka. The barrage diverts water from the Ganga to the Hooghly River to maintain the river's navigability and prevent siltation in Kolkata's port. This project has significant implications for water management and environmental concerns in both India and Bangladesh.
3. **Historical and Cultural Importance**: The Ganga river holds immense religious and cultural significance in India. The easternmost point of the Ganga in West Bengal, Farraka, is an important site for pilgrims and is often visited for religious purposes.
Understanding the geographical layout of the Ganga river in West Bengal is essential for comprehending the region's hydrology, ecology, and socio-economic dynamics. The river's easternmost point at Farraka is a critical juncture that influences water distribution, agriculture, and urban development in the region.
In contrast, the other options provided are not relevant to the easternmost point of the Ganga in West Bengal:
- **Devaprayag** is the confluence of the Alaknanda and Bhagirathi rivers, forming the Ganga, and is located in Uttarakhand.
- **Allahabad (Prayagraj)** is a city in Uttar Pradesh where the Ganga, Yamuna, and mythical Saraswati rivers meet.
- **Bhagirati** is a tributary of the Ganga that merges with the Alaknanda at Devaprayag.
Thus, Farraka is the correct answer as it is the easternmost point of the Ganga river in West Bengal, marking the river's split into the Hooghly and Padma branches and the location of the Farakka Barrage.