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You must figured out the three correct answers of the riddles that can be found in the books in the previous rooms.
There should be 3 books, that act as riddles, and when you solve these riddles, you will know which items you need to pick to open the door.
The 3 books/riddles can be found in the book what you have in your inventory (not the quest journal).
But If you can't figured it out by yourself, the 3 objects what you need to pick are Ring, Locket and Dress, If I recall correctly.