Select the sentence below that uses proper punctuation to separate a nonessential phrase from the main sentence.

A. Pocahontas saw a man with yellow hair walking through the forest — a sight she had never seen before — so she followed him.
B. Pocahontas saw a man — with yellow hair — walking through the forest a sight she had never seen before so she followed him.
C. Pocahontas saw a man with yellow hair — walking through the forest — a sight she had never seen before so she followed him.
D. Pocahontas saw a man with yellow hair walking through the forest a sight she had never seen before — so she followed him.