I'm taking a test and have to guess the right answer to the question after the article. Article: If you knew a bottle of water had been recycled from urine , would you drink it? Astronauts at the International Space Station (ISS) may soon do so. NASA said it would use a high-tech machine to recycle wastewater at the ISS. The machine will recycle everything from sweat , the water for washing hands, shower water, water used for brushing teeth, and even urine, to make drinking water. It will save NASA millions of dollars each year. At present, each ISS astronaut uses about 4.4 liters of water every day. It costs about $24 million a year to transport water up to ISS. NASA says that a liter of water costs about $11,000. The machine will be sent to the ISS in October 2008. NASA hopes it will recycle about 93% of all water used on the station. Will the water be clean? Scientists say the wastewater will go through a very complicated process . For example, different chemicals will be put in the wastewater; the water will be heated to 130degCto get rid of bacteria . The recycled water is thousands of times better than the water from a city tap, scientists say. Question: The reading mainly tells us something about _ . Options: A: water recycling B: the International Space Station C: a high-tech machine D: the cost of NASA
The answer to this question is:
C