The correct option is 1 and 3 only
Explanation
The Ganga river system originates in the Central Himalayas. It is primarily formed by two main headstreams, the Bhagirathi and the Alaknanda, which unite at Devprayag to officially form the river Ganga.
Statement 1 is Correct: The Bhagirathi is traditionally considered the source stream of the Ganga. It rises from the Gangotri Glacier near Gaumukh in the Uttarkashi district of Uttarakhand at an elevation of approximately 3,900 meters.
Statement 2 is Incorrect: The Alaknanda originates from the Satopanth Glacier above Badrinath. The Milam Glacier is the source of the Goriganga river, which is a tributary of the Kali (Sarda) river.
Statement 3 is Correct: The Alaknanda is formed by the confluence of the Dhauli and the Vishnu Ganga rivers. These two streams meet at Vishnuprayag, which is located near Joshimath. From this confluence onwards, the river is known as the Alaknanda.
Key Takeaway: The Ganga is formed by the confluence of the Bhagirathi (from Gangotri) and the Alaknanda (from Satopanth) at Devprayag. The Alaknanda itself begins at the confluence of the Dhauli and Vishnu Ganga at Vishnuprayag.