The formation of cirques and its associated landforms are created through the process of plucking and abrasion (A). Plucking (also known as 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 erosion caused by rock particles carried by the glacier. These particles act like sandpaper smoothing rock surfaces and / or creating striations on rock surfaces over which the glacier flows.

The other choices do not work because they are only partially correct. For example, with option C quarrying is correct but salinization does not apply here as it involves the accumulation of soluble salts in topsoils such as in a hot desert. With option D, frost shattering (also known as freeze thaw action) is correct but saltation (the rolling of rock materials on a river bed) does not fit. Finally, ice-wedging would seem to fit but deflation (i.e. wind removal of loose, dry material from the land surface such as in a hot desert) does not apply.

Hence, you must find the pair that are both correct.