Which of the following is the best example of a frame narrative?

ABarnyard animals conspire to overthrow the humans on the farm and start their own government.

BA boxer tries to put himself in the mind-set of his opponent, but his dislike for the man overcomes his empathy.

CA detective discovers that the kidnapper she's been investigating is actually her other personality.

DFour survivors of World War II sit around a table and share their war stories with a naïve reporter.