Read this summary of the selection.
In the 1850s, Chicago fell victim to disease outbreaks caused by standing
water. To prevent the epidemics, the city needed a sewer, but it sat too close
to the water table. For more than a decade, engineers and workers lifted
buildings and moved them on rollers to make room for the new sewer system.
Which important detail is missing from this summary?
A
The city tried cheap solutions like grading the streets and installing wooden
boardwalks
B
B.
Before a sewer could be installed, the city's elevation had to be raised.
C
Workers also lifted sidewalks, streetlights and other parts of the city's infrastructure.
D.
In 1854, six percent of the city's population died during a cholera outbreak.