Kosi River is linked with which river system?

Correct answer: Ganga system

Direct answer: Option B, the Kosi belongs to the Ganga river system. Kosi is a Himalayan tributary that flows through Nepal and Bihar and joins the Ganga near Kursela. Step by step: Himalayan rivers descend toward the northern plains; Kosi carries water and sediment southward; it joins the Ganga; therefore it is part of the Ganga system. Option A, Indus system, is wrong because Kosi does not drain into the Indus. Option B is correct because the Ganga is its main river system. Option C, Kaveri system, is wrong because Kaveri is a peninsular river of southern India and Kosi is a Himalayan river. Option D, Narmada system, is wrong because Narmada flows westward separately toward the Arabian Sea. Kosi is also famous for frequent channel shifting and floods in Bihar, which is a useful supporting clue, but the direct reason for the answer is its confluence with the Ganga. Memory cue: Kosi—Ganga—Bihar floods.