Answer: A. People who have good fortune should not expect it to last forever.
The monk from Chaucer's "The Monk's Tale" would most likely agree with the statement of option A because this is the main theme of this tale. The monk tells some tragedies (he had much more to tell) about people who were in high positions and had great prosperity but fell in misery. The purpose of the tales is to warn people about the fortune's fickleness.