Question: Yvonne Mounsey, the South African-American ballet dancer was known for the important roles she created in the works of which choreographer who co-founded the New York City Ballet?
{'answer': 'George Balanchine', 'supporting_facts': [['Yvonne Mounsey', 0], ['Yvonne Mounsey', 1], ['George Balanchine', 1]]}