The correct answer is: A. Kanchi River
The Kanchi River is a river in Jharkhand, India. It is a tributary of the Damodar River. The Kanchi River originates in the hills of the Chhotanagpur Plateau and flows through the districts of Ranchi, Hazaribagh, and Ramgarh. The river is about 200 kilometers long. The Kanchi River is a major source of irrigation for the region. It is also a popular tourist destination. The Dassam Waterfall is located on the Kanchi River. The waterfall is about 100 meters high and is one of the most popular tourist attractions in Jharkhand.
The other options are incorrect because they are not rivers that form the Dassam Waterfall. The Banoi River is a tributary of the Kanchi River. The Ramgarh River is a tributary of the Son River. The Burha River is a tributary of the Damodar River.