Question: Elizabeth at 90: A Family Portrait is narrated by the longest-serving heir apparent in what?
Sentence (from "Elizabeth at 90: A Family Portrait"): The film featured contributions from the Queen, the Prince of Wales, Anne, Princess Royal, Prince William, Duke of Cambridge and Prince Harry, Lady Sarah Chatto, Prince Edward, Duke of Kent and Princess Alexandra, The Honourable Lady Ogilvy.
Relevant evidence: No