You chose to lead the King of Hearts. This is not a good lead. You at this stage don't know who has the Ace of Hearts, which is bigger and therefore will beat your King. It might be your partner, in which case, no harm will have been done. But it is equally likely to be the opposition, and you will have given them a trick and lost one of your few good cards in the process. Go back to Question 8 and choose again.