You are given an English sentence with a blank, and you need to predict the missing word. After completing, the whole sentence should be gramatically correct and non-ambiguous.
Q: and believed firmly in her daughter's innocence and fidelity to the paternal roof she listened at eugenie's ____ and hearing no sound tried to enter but the bolts were in place madame danglars then concluded that the young girl had been overcome with the terrible excitement of the evening
A: 
door