Why Correct: The active delta of the Ganga River in India is located in the Sundarbans region, where the river deposits sediment and forms new land through distributaries.
Distractor Analysis: Nadia district lies upstream in the mature delta region. North 24 Parganas and South 24 Parganas contain parts of the Sundarbans but the active delta specifically refers to the mangrove forest area. Medinipur East is in the western part of West Bengal, outside the delta region.
Takeaway: The Sundarbans is the world's largest mangrove forest and a UNESCO World Heritage Site, shared between India and Bangladesh.