The unique phenomenon you described, where the seawater recedes several kilometres twice a day, exposing the seabed for walking, can be seen at Chandipur Beach in Odisha, India.

Chandipur Beach is also known as the "hide-and-seek beach" due to this fascinating tidal phenomenon. The receding water allows visitors to explore the seabed, revealing seashells and marine life during low tide.

Hence, option C is the correct answer.