Concept:A river mouth often develops into a delta when sediment is deposited as the river enters a standing body of water.
Explanation:The mouth of River Bala is the point where the river meets a larger water body or a flat coastal area.
As the river slows down there, it loses energy and drops the sediment it has been carrying.
This deposited sediment builds up over time and may split the river into several smaller channels called distributaries.
Such a feature formed at a river mouth by sediment deposition is known as a delta.
A waterfall forms on hard rock, river capture involves stream erosion, and a saddle is a ridge feature, so they do not fit the river mouth.
Answer:D. delta
