"Because of a funeral" is a perfectly adequate answer to this question, as written. If the setter wanted to know whose funeral it was (as the person who asked me the question felt they did), they should have asked "Prince Charles's marriage to Camilla Parker Bowles was postponed for 24 hours because of whose funeral?"
As I've pointed out more than once this season, the Guidance for Question Setters advises: "Do not include questions with more than one, or indeed multiple, answers. Make sure each question you have written only has ONE correct answer."
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