The answer is:
D) tragedy
Tragedy in the medieval ages was seeing not as the result of someones missbeheaving, their own character flaws rather than a turning in the wheel of fortune, they portrayed the idea thru litereature that some men the gods were on their favor, and some other they weren´t, this meant that fortune or destiny was decided by god just as in the Greek tragedies.
The right answer is "A. The clergy "
You should be referring to the quote from "The Canterbury Tales" where the word gold is used to represent the clergy in all its purity that leaves it in such a high standard that nothing can reach it, just as gold can not be attained by rust.
I believe that the answer is either C, or D. They both seem plausible.
To be nice, strong, and yeah.