The correct option is D Volume of sediments in the river
The variety of landforms formed by rivers is based upon various factors such as the volume of flowing water and the volume of sediments in the water. Erosional landforms are formed in the youthful stage as it has more energy and power. The speed of the flow of the river decreases in flatter regions. Here, the eroded sediments start getting deposited. Thus, running water creates a variety of landforms through erosion, transportation, and deposition.