The only original part remaining of the Parliament Buildings after the 1916 fire is the:

Discover Canada records this in one direct sentence. The guide writes: The buildings were completed in the 1860s. The Centre Block was destroyed by an accidental fire in 1916 and rebuilt in 1922. The Library is the only part of the original building remaining. The original part the test wants is therefore the Library.

Three building events anchor the story. Discover Canada commits the Parliament Buildings to THREE specific events: (1) completed in the 1860s; (2) Centre Block destroyed by an accidental fire in 1916; and (3) rebuilt in 1922. So the Centre Block we see today is the post-1916 rebuild, not the original 1860s structure. Only the Library survived the fire.

The Library is uniquely original. Discover Canada commits the Library to a unique status: the only part of the original building remaining. So among all the Parliament Buildings on Parliament Hill, the Library is the only piece that dates back to the original 1860s construction. Everything else was rebuilt after 1916. The Library's survival was a remarkable event during the fire — likely due to fire doors that were closed in time.

The Peace Tower came later. Discover Canada writes: "The Peace Tower was completed in 1927 in memory of the First World War. The Memorial Chamber within the Tower contains the Books of Remembrance in which are written the names of soldiers, sailors and airmen who died serving Canada in wars or while on duty." So the Peace Tower (1927) is part of the post-fire rebuild — not part of the original Parliament Buildings. Together, the original 1860s Library, the rebuilt 1922 Centre Block, and the 1927 Peace Tower form the modern Parliament Hill ensemble. The buildings reflect Gothic Revival architecture popular in Queen Victoria's time, and they stand on Parliament Hill in Ottawa — Canada's capital chosen in 1857 by Queen Victoria. So when the test asks the only original surviving part after the 1916 fire, the source-precise answer is the Library.

The question is testing whether new citizens know which part of the original Parliament Buildings survived the 1916 fire. Discover Canada commits to one part: the Library. The right test answer matches that.

The wrong answer choices each substitute a different building component. "Peace Tower" was completed in 1927 — it was a NEW addition AFTER the fire, not an original part. The second-option chamber was rebuilt as part of the 1922 Centre Block restoration — not an original surviving piece. "Centre Block entrance" is part of the rebuilt Centre Block — also not original. Only the Library — the source's named only-original-remaining part — matches.