Answer:
D. a canyon
Explanation:
This answer could depend on the photo but a canyon is formed by water traveling through the landform for a long time and a plateau is a raised area of land. but due to it being a deep valley it is more likely to be a canyon. an isthmus is a narrow price of land surrounded by water on two sides and an estuary is the area where I river meets the ocean tide. This answer would be better if the picture was provided but I hope that I could help :)