Concept:Headward erosion is the backward cutting of a river at its source, which may extend the river channel and alter local drainage patterns.
Explanation:As a river erodes backward at its head, it gradually lengthens its course toward higher land.
This backward cutting may continue until the river meets and intercepts the channel of a neighbouring river.
When this happens, the stronger river captures the flow of the weaker river, a process known as river capture or stream piracy.
Thus, headward erosion does not form potholes, oxbow lakes, or alluvial cones, as those features are produced by other fluvial processes.
Answer:B. River capture.