GMAT Sentence Correction (SC) | Re: The structures designed by Ralph C. Harris were fifteen- and seventeen

Source: McGraw Hill GMAT 2013

The structures designed by Ralph C. Harris were fifteen- and seventeen-story buildings, and for theirtime, were some of the larger and more luxurious hotels and residences in existence.

A. time, were some of thelarger and more luxurious hotels and residences
B. era, they were some of thelarger and more luxurious hotels and residences
C. era, were some of the largest andmore luxurious hotels and residences
D. time, they were some of thelargest and most luxurious