Artistically, Okonkwo's seven years' exile is a device used by Achebe to

• A.to introduce comic relief
• B.keep Okonkwo at a distance from the movement of the mind of Umuofia
• C.serve as a warning to other members of the Umuofia community
• D.shows that wilful crime does not pay
• E.de-emphizes the role of Okonkwo in the novel