Question: Within Four Corners of the United States, which unit of the National Park Service has ruins of the indigenous tribes and is within the boundaries of the Navajo Nation?
{'answer': 'Canyon de Chelly National Monument', 'supporting_facts': [['Four Corners', 5], ['Canyon de Chelly National Monument', 0], ['Canyon de Chelly National Monument', 1], ['Canyon de Chelly National Monument', 2]]}