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The answer to your question is that both the CIA and Canadians were responsible for the escape of the American diplomats. The Canadian Broadcasting Corporation, Central Intelligence Agency, Al Jazeera, Ottawa Citizen, New York Times, Montreal Gazette, and many other sources confirm the story.
Once the crisis started the CIA contacted the Canadians in Tehran, and coordinated with them to ensure the escape of the American diplomats. That is what the facts tell us because that is what happened.