According to the passage, what is one disadvantage of skyscrapers that have mirrored walls A: The exterior surrounding air is heated. B: The windows must be cleaned daily. C: Construction time is increased. D: Extra air-conditioning equipment is neede

According to the passage, what is one disadvantage of skyscrapers that have mirrored walls A: The exterior surrounding air is heated. B: The building materials are very expensive. C: Construction time is increased. D: Extra air- conditioning equipment is neede