I think the theme of "Young Goodman Brown" is (D) The forest is a place where dark deeds take place.
This is because the author likens the forest to the unseen and naturally Goodman Brown expresses his distrust and fear as he cautiously enters it. The forest reflects the views of the 17th century Puritans who initially feared the forest but then also wanted to dominate it once they had overcome their fears. Goodman Brown also sees the Devil himself in the forest.
