Concept:A stack is formed by the continuous erosion of a headland through specific stages.
Explanation:The process begins with a headland jutting out into the sea.
Waves attack the headland and create a cave through erosion.
Further erosion widens the cave into an arch.
When the roof of the arch collapses, a stack is formed.
Thus, the correct order is: headland, cave, arch, stack.
This matches option B.
Answer:B. headland, cave, arch, stack