The correct answer is: d. Burhi Gandak meets Ganga at Karhagola.
The Phalgu River meets the Ganga at Munger. The Kamla River meets the Ganga at Surajgarha. The Kosi River meets the Ganga at Chhapra.
The Burhi Gandak River is a tributary of the Ganges River. It originates in the Himalayas and flows through the Indian states of Uttarakhand, Uttar Pradesh, Bihar, and Jharkhand. The Burhi Gandak meets the Ganges at Karhagola, a town in the Indian state of Bihar.