Which one of the following is the best example of repeated falls in sea level, giving rise to present-day extensive marshland?

Answer: (d) Rann of Kutch

The Rann was once an arm of the sea; repeated falls in sea level and uplift left a vast seasonal salt marsh.

The idea

A fall in relative sea level exposes a former shallow marine floor. On flat ground, flooding and strong evaporation can then produce a seasonal saline marsh. Relative level depends on both the sea surface and land movement, so the landscape is not explained by evaporation alone.

Shallow marine setting → Relative sea level falls → Flat seabed is exposed → Seasonal water spreads over low ground → Water evaporates in dry weather → Saline marsh and salt crust remain

Why the others are wrong

(a) Bhitarkanika is a mangrove delta.

(b) Marakkanam salt pans are man-made.

(c) Naupada swamp is a coastal swamp in Andhra.

Also know

The Great Rann and Little Rann are separate parts of the Kachchh salt-marsh landscape. The Little Rann supports the Indian wild ass. Bhitarkanika is a tidal mangrove setting in Odisha, while engineered salt pans are made to concentrate seawater; natural coastal change and salt production are different processes.