The northern plains are formed by :
interplay of Himalayan rivers
(B) By the interplay of three river systems Indus, Ganga, and the Brahmaputra
Explanation
The Northern Plain was formed by the deposits brought in by the three major rivers and their tributaries.
Due to the rising of the Himalayas in the Tethys Sea, the northern portion of the Indian Peninsula has sunk and produced a vast basin. The basin was filled with sediments from rivers that flowed from the mountains in the north and the peninsula in the south. The huge alluvial deposits were influenced by the creation of India’s northern plains. The world’s greatest alluvial stretch is found in the northern plains. These plains stretch about 3200 kilometres from west to east. Three river systems, the Indus, Ganga, and Brahmaputra, are responsible for India’s northern plain and its tributaries. These grasslands cover a span of 150 to 300 kilometres on average.