The answer is B. Cauvery.
The other three rivers, Mahanadi, Narmada, and Krishna, are all located in India. The Cauvery River is located in India and Sri Lanka. It is the longest river in the Indian state of Tamil Nadu and the second-longest river in the Deccan Plateau. The Cauvery River is a major source of water for irrigation and drinking water for millions of people in India and Sri Lanka.
The Mahanadi River is the longest river in the Indian state of Odisha. It is the fifth-longest river in India. The Mahanadi River is a major source of water for irrigation and drinking water for millions of people in Odisha.
The Narmada River is the longest river in the Indian state of Madhya Pradesh. It is the seventh-longest river in India. The Narmada River is a major source of water for irrigation and drinking water for millions of people in Madhya Pradesh.
The Krishna River is the second-longest river in the Indian state of Andhra Pradesh. It is the tenth-longest river in India. The Krishna River is a major source of water for irrigation and drinking water for millions of people in Andhra Pradesh.