During the Glacial erosion by abrasion the glaciers are loaded with other rock fragments as a tool for erosion of the bedrock. These rock fragments are dragged on the bedrock during the forward movement of the glacier and causes the rocks that comes in contact to abrade and the process is known as abrasion.
These abraded mass can also get trapped in the glacier as sub glacial, intra glacial and even super glacial deposit , causing the glacier to increase in mass and hence may flow easily where the glacier flow because of gravity. Abrasion also causes melting of snow because of the frictional heat produced during interaction of rock fragments and country rock.
option D