The correct answer is:
Julie’s opponent wins the point, and the point shouldn’t be replayed since Julie missed the return before calling the let.
From the Code, Item 36:
In professional tennis, you will never see a player stop a point because the opponent has fallen. However, according to the Code, if something happens that could be seen as a hindrance, the opponent may immediately call a let due to hindrance. In this case, since Julie attempted to return the ball, her let call was too late. If she had stopped the point immediately, she could have called a let.
To clarify, the let can be called because the player who did not fall was hindered by the fallen player. A let cannot be called out of concern for the fallen player.
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