At one of the places in India, if you stand on the seashore and watch the sea, you will find that the sea water recedes from the shore line a few kilometres and comes back to the shore, twice a day, and you can actually walk on the sea floor when the water recedes. This unique phenomenon is seen at

The unique phenomenon of seawater receding several kilometers from the shoreline, allowing people to walk on the seabed, is observed at Chandipur-on-sea in Odisha.

During the ebb tide (the period between high tide and low tide), the water recedes up to 5 kilometers at Chandipur beach.

Hence, the correct answer is Chandipur.

Sources:

• Wikipedia - Chandipur, Odisha