Correct option is D
The correct answer is (D) Mahanadi
The Mahanadi is not a tributary of the Ganga but flows directly into the Bay of Bengal.
The Mahanadi flows through the states of Chhattisgarh and Odisha before draining into the Bay of Bengal.
Gomti, Ghaghara, and Kosi are all tributaries of the Ganga:
Gomti: A major tributary flowing into the Ganga at Jaunpur, Uttar Pradesh.
Ghaghara: A large tributary that originates in Tibet and joins the Ganga in Uttar Pradesh.
Kosi: Originates in the Tibetan Plateau and joins the Ganga in Bihar.