Where in the passage does the author compare the energy consumption of skyscrapers with that of a city

A．The noise from their construction
B．The removal of trees from building sites
C．The harmful effects on the city's grass
D．The high cost of rentable office space

A．compare skyscraper's with other modern structures
B．describe skyscrapers and their effect on the environment
C．advocate the use of masonry in the construction of skyscrapers
D．illustrate some architectural designs of skyscrapers