What Is the Relationship Between Plucking and Abrasion on a Glacially-Scoured

What is the relationship between plucking and abrasion on a glacially-scoured landscape?

A) Plucking occurs relatively suddenly when a glacier first encounters the landscape, and then if it remains in place for a long time, abrasion begins to happen later, over a long period of time.
B) Abrasion occurs relatively suddenly when a glacier first encounters the landscape, and then if it remains in place for a long time, plucking begins to happen later, over a long period of time.
C) Plucking occurs on the upflow side of a mound or hill that is scoured, while abrasion occurs on the downflow side.
D) Abrasion occurs on the upflow side of a mound or hill that is scoured, while plucking occurs on the downflow side.