Explanation

The Manas is a major right-bank tributary of the Brahmaputra, rising in Bhutan and joining the Brahmaputra in Assam. The Ghaggar is an inland-drainage river of Haryana and Rajasthan that does not reach the sea or the Brahmaputra. The Mahi flows westward into the Gulf of Khambhat in Gujarat. The Kosi is a tributary of the Ganga, not the Brahmaputra. Hence option D is the correct answer.