Answer:
To correctly punctuate the sentence, we must:
A. Add a comma after the word dark.
D. Add a comma after the word evil.
Step-by-step explanation:
We must use a comma to separate coordinate adjectives in a sentence. Coordinate adjectives have the same degree of importance in the structure and describe the same noun. The sentence we are analyzing here uses coordinate adjectives in "evil mad scientist" and "dark distant mountains". However, the punctuation is off. To correct it, we must add a comma after "evil" and another after "dark":
- The unicorns know of an evil, mad scientist who lives beyond those dark, distant mountains.