Question: What American Socialite married the elder son of Edward Cavendish?
{'answer': 'Kathleen Agnes Cavendish', 'supporting_facts': [['William Cavendish, Marquess of Hartington', 0], ['William Cavendish, Marquess of Hartington', 1], ['William Cavendish, Marquess of Hartington', 2], ['Kathleen Cavendish, Marchioness of Hartington', 0]]}