Which river forms a huge delta in the Bay of Bengal after originating in the Himalayas?

Correct answer: Ganga

The correct answer is the Ganga. The river rises in the Himalayan region, receives numerous tributaries across the northern plains, and carries substantial sediment eastward. Near the Bay of Bengal, its flow divides into distributaries and contributes, together with the Brahmaputra and Meghna systems, to the enormous Ganga-Brahmaputra delta. Narmada flows west through a rift valley into the Arabian Sea, while Luni ends in the arid region of Rajasthan and Sabarmati also drains westward into the Arabian Sea. Hence option A best fits both the Himalayan origin and the Bay of Bengal delta described.