21. The author refers Humpty Dumpty’s remarks to Alice in order to .
(A) emphasize that the word hope is created with an effort to mean what it intends to mean
(B) suggest the analogy of Humpty Dumpty’s effort to fall has been underappreciated
(C) explain how Lewis Carroll created Humpty Dumpty to sit on the wall and to fall
(D) underscore the author’s immense contribution to cancer patients at end stage