Given those answer options, answer the question: Read the following article and answer the question. Article: More and more schools are being designed and used in ways that are friendly to the environment. These so-called green schools use less energy, cost less to run and are good for students. The newly renovated Sidwell Friends Middle School in the District has been awarded the highest rating by the U.S. Green Building Council for having a positive impact on the environment-a rare honor. Soon the school will treat and re-use its wastewater, saving hundreds of thousands of gallons of water per year. The recycled water from sinks and toilets, which can't be used for drinking, will be color1ed blue, "so we know it's recycled, just in case it gets into the water fountains -not that it would," joked Emily Bernstein, 14, a Sidwell student and building tour guide. Water fountains will still use fresh city water. Sidwell students are studying the building itself in science classes to help them learn first-hand the positive impact of green buildings. It's affecting how they view the world around them. "If you see a [building] being torn down, you think, 'They're going to fill up a whole landfill with that,'" said Matthew Malone, 13. In Prince George's County, Suitland Elementary has been so successful that another green school is being planned, in Laurel, for the 2008-09 school year. At Suitland, a garden courtyard collects and uses rainwater; the roof is angled away from the sun to keep it cool; and skylights and tall windows let in lots of natural light. "You don't have to switch on the light switch all the time," said Rupert McCave, the county official guiding these projects. Green schools tend to be sunnier and more _ than older buildings. In fact, a study done inprefix = st1 /Washingtonstate showed that students at green schools performed better and were absent less. Question: The passage is mainly about_. Answer:
A:
environmentally-friendly schools