The Northern Plains lie south of which major mountains of India?

Correct answer: Himalayas

The direct answer is C: the Northern Plains lie south of the Himalayas. Rivers descending from the Himalayas, especially the Indus, Ganga, and Brahmaputra systems, carry sediments and deposit them over a broad lowland. This creates the extensive Northern Plains between the Himalayan foothills and the Peninsular Plateau. Option C is correct because the Himalayas form the major northern boundary of these plains. Option A is wrong because the Aravalli range is in western India and does not form the northern boundary of the Northern Plains. Option B is wrong because the Western Ghats lie along the western edge of the Deccan region. Option D is wrong because the Nilgiri Hills are in southern India. The question asks for the major mountain system immediately north of the plains, so choose Himalayas. Memory cue: Himalayas above, alluvial Northern Plains below.