Concept:The upper course of a river is distinguished by steep slopes, fast current, and dominant vertical erosion, leading to the formation of a V-shaped valley.
Explanation:During the upper course, the river cuts downward rapidly because it has great energy and a steep gradient.
Vertical erosion deepens the river channel more than sideways erosion widens it.
The valley sides remain steep and narrow, giving the characteristic V-shape.
An ox-bow lake is a crescent-shaped waterbody formed later in the lower course when a meander loop is cut off.
Meanders are winding bends typical of the middle and lower courses, where lateral erosion is dominant.
An artificial embankment is a man-made ridge built to prevent flooding; it is not a natural river-landform feature.
Answer:C. V-shaped valley