Unlike smaller apartment buildings, which have fewer than four
residential units in them, each room within any residential complex must be equipped with a sprinkler system.

A) Unlike smaller apartment buildings, which have fewer than four
residential units in them
B) Apart from those apartments that are in buildings that contain
fewer than four residential units
C) In contrast to smaller apartment buildings that contain fewer than
four residential units
D) Unless the apartment building contains fewer than four residential
units
E) Excluding those apartment buildings that have fewer than four
residential units in them