The correct option is (c).
Explanation
Rivers modify the landscape through erosion, transportation, and deposition. In the lower course (old stage), the river's velocity decreases significantly, leading to the formation of specific depositional landforms such as floodplains, levees, and deltas.
Statement-wise Analysis:
- Statement 1 is Incorrect: The raised banks of a river are called natural levees, not deltas. Levees are formed when a river floods and deposits coarse sediments along its immediate banks, creating ridges that stand higher than the surrounding floodplain. A delta is a triangular landform created at the river mouth.
- Statement 2 is Correct: As the river approaches the sea, the slope of the riverbed becomes extremely gentle. Consequently, the speed of the water flow decreases. The river becomes sluggish and begins to break up into numerous channels called distributaries.
- Statement 3 is Correct: Due to the reduced speed, the river loses its capacity to carry sediments. It deposits its load of silt and clay at the mouth. The collection of sediments from the mouths of all distributaries accumulates to form a fan-shaped or triangular landform known as a delta.
Key Takeaway:
Natural Levees are raised banks formed along the river channel due to flood deposition, whereas a Delta is a depositional feature formed at the river mouth where it meets a standing body of water.