Hey there Amazing Moderator!
Your question states: Which of the following provides the best example of foreshadowing in "The Nun's Priest's Tale"?
I believe that the correct answer should be A.) Chanticleer's dream
Reason: The reason why I would say the the correct answer would be A.) is because a foreshadow would be something that can happen in the future of the story. Which concludes that Chanticleer would dream of something that could happen later on in the dream.
I believe that your correct and final answer would be [tex]\boxed{ Chanticleer's \ dream}[/tex]
_____________________________________________________________
I really hope this can help you [tex]SlipKnot[/tex]
~Jurgen