Which detail from the passage BEST supports the idea that green roofs can help cities decrease their power consumption?
A.
City planners all over the country are initiating the installation of green roofs.
B.
Over 400 green roof projects are being developed in Chicago.
C.
Rooftop gardens can improve air quality and reduce stormwater runoff.
D.
Energy costs at City Hall in Chicago decreased after a green roof was installed there.