Plucking and abrasion (A) are the two processes responsible for shaping the features mentioned in the diagram. Plucking or quarrying is a glacial erosion process whereby protruding or fractured rock surfaces are frozen to the glacial ice and broken free from bedrock. Abrasion is bedrock erosion caused by rock particles embedded in the glacier wearing down the surfaces that they come in contact with.

B will not work because attrition is the gradual wearing down of rock fragments as they make contact with each other, for example in a river or in waves along a coastline.

C will not work as corrosion is a gradual eating away due to a chemical reaction.

D will not work because deflation is applicable to a dry, windy area where the land is being lowered due to the removal of loose sand or rock fragments.