What Separated Geoffrey Chaucer, the Author of the Canterbury Tales

What separated Geoffrey Chaucer, the author of The Canterbury Tales, from previous writers of travelogues?

A) He wrote about unique, imaginary creatures as well as well-known mythical figures.
B) He wrote frankly and realistically about pilgrims from many levels of society.
C) He was the first author of note to write in Middle English.
D) He was the first secular author to write in English.
E) He made no comments about religious figures; his work focused strictly on secular characters.