Question: The husband of Kathleen Kennedy was heir apparent to the 10th Duke of where?
Sentence (from "Kathleen Cavendish, Marchioness of Hartington"): Kathleen Agnes Cavendish, Marchioness of Hartington ("née" Kennedy; February 20, 1920 – May 13, 1948), also known as "Kick" Kennedy, was an American socialite.
Relevant evidence: No