Correct option is C
The correct answer is (C) Koyna
The Mahi River flows through Rajasthan and Gujarat and eventually drains into the Gulf of Khambhat.
The Sabarmati River also originates in Rajasthan, passing through Gujarat, and empties into the Gulf of Khambhat.
The Tapti River originates in Madhya Pradesh and flows westward through Maharashtra and Gujarat, emptying into the Gulf of Khambhat.
Koyna is primarily a tributary of the Krishna River, and it does not reach the Gulf of Khambhat.
Mahi : The Mahi River flows into the Gulf of Khambhat after traversing through Gujarat.
Sabarmati : The Sabarmati River also empties into the Gulf of Khambhat, passing through Ahmedabad and other parts of Gujarat.
Tapti : The Tapti River, flowing from the Satpura Range, empties into the Gulf of Khambhat after crossing Maharashtra and Gujarat.