Explanation:

- Option 1: Golden bracelet was not involved in the scandal that damaged Marie Antoinette's reputation.

- Option 2: Sapphire brooch is not related to the scandal in question.

- Option 3: Silk dress, while indicative of luxurious spending, was not central to the specific scandal damaging her reputation.

- Option 4: Diamond necklace is correct. The Affair of the Diamond Necklace was a major scandal that tarnished Marie Antoinette's reputation, as it involved deceit and fraud over an expensive necklace she was falsely accused of purchasing.