b) provide comic relief
&
d) offer parallels to Faustus's character
are both correct
B
because when describing a noun with adjectives, you can say: that is a green salad. but if the salad is also big I can say: that is a big, green salad.
The correct answer is : The well-known artist arrived.
"well-known" is a compound modifier and, in the sentence above, is used immediately before the noun it modifies. For that reason, it must be hyphenated.
"chocolate-covered" could be hyphenated as well, but its location in the structure is improper for that use, since it comes after the noun it modifies.