The only reason the party was a success was that a famous film star attended.

• A. Had it not been for the attendance of a famous film star, the party would not have been a success.
• B. Hadn’t it been for the attendance of a famous film star, the party would not have been a success.
• C. Had the party not been a success, a famous film star wouldn’t have attended.
• D. Hadn’t the party been a success, a famous film star wouldn’t have attended.