The correct answer is option 4 - Devprayag. Devprayag is the place located at the confluence of the Alaknanda and Bhagirathi rivers in Uttarakhand, India. The Alaknanda river is one of the main tributaries of the Ganges River and the Bhagirathi river is another important tributary.

Option 1 - Badrinath is a famous Hindu pilgrimage site located in Uttarakhand, but it is not the confluence of the Alaknanda and Bhagirathi rivers.

Option 2 - Rishikesh is another important city in Uttarakhand, known as the "Yoga Capital of the World" and is also located on the banks of the Ganges River. However, it is not the confluence of the Alaknanda and Bhagirathi rivers.

Option 3 - Rudraprayag is a town located in Uttarakhand, where the Mandakini River meets the Alaknanda River. It is an important pilgrimage site, but it is not where the Alaknanda and Bhagirathi rivers meet.

Therefore, the correct answer is option 4 - Devprayag, as it is the place where the Alak