Which of the following is a difference between internal and external whistle-blowing?

		Unlike internal whistle-blowing, the history of external whistle-blowing is impossible to track.
		Unlike external whistle-blowing, the examples of internal whistle-blowing receive no media attention.
		Unlike internal whistle-blowing, incidents of external whistle-blowing are rarely documented.
		Unlike external whistle-blowing, internal whistle-blowing does not harm a company's public image.