I'd like to try to take a stab at this....I chose E.
While closed to the public during the entire decade of the 1990s, the Italian government undertook extensive renovations to stabilize the Leaning Tower of Pisa while preserving some of its famous tilt.
A) While closed to the public during the entire decade of the 1990s Eliminate: extraneous information "While closed during the 1990s" could have summarized this better.
B) During the entire decade of the 1990s, while closed to the publicEliminate: extraneous information "While closed during the 1990s" could have summarized this better as well.
C) Beginning in the 1990s after closing it to the publicEliminate: extraneous information "After closing it to the public in the 1990s" might be a better choice.
D) Closing the landmark to the public beginning in the 1990sEliminate: extraneous information "After closing it to the public in the 1990s" might be a better choice.
E) In the 1990s, during which the landmark was closed to the publicMy choice: The temporal relationship between the two statements match. When it was closed...they did this.
What's the right choice?