D. While witch hunts may feel like a rare occurrence, such incidents are not uncommon in history, especially when people are fearful or frustrated.
This is the best answer to the question. The central idea of a text is what the whole text is about. The first clue that option D is the best answer is the title of the text "The Salem (and Other) Witch Hunts". This title shows the reader that the article will be about many different witch hunts. This eliminates option A. The other two options suggest that there were other witch hunts, but that the Salem witch trials were particularly rare or unique. However, this is not what the article states. In fact it says that “The Salem episode was a historic landmark but by no means a rare example of behavior that can afflict frightened, angry, or frustrated people” (Paragraph 13). This supports the central idea that witch hunts aren't actually that rare especially when people are afraid.