I'm taking a test and have to guess the right answer to the question after the article. Article: You've got plenty of emails from your mom, and maybe even a few from dear old grandma. But have you ever received a message from a river? Now, Ireland's River Lee is sending out much information, thanks to wireless technology. In a program called the DEPLOY project, scientists have put some sensors in rivers that can find pollution levels. Instead of asking scientists to collect water _ several times a day, the government can now examine pollution levels in the water, and find out if there is anything polluted entering the river. This makes it much easier for scientists to protect the environment, since problems can be discovered before a serious pollution accident really happens. People in the area can also receive free reports from the river, so that they can find out whether the water is safe for swimming or boating on a certain day. And people can also know if the water is clear enough for them to drink and use. The DEPLOY project has not only started in Ireland, also the same programs have started in thousands of places around the U.S. Now you live in a world in which you could receive information with your mobile phone about environment. The technology should help to make us know more about the pollution that surrounds us--which just might get us all a little more involved with trying to clean up our world. Question: How do scientists find pollution levels in rivers? Options: A: By putting sensors in rivers. B: By using mobile phones. C: By boating or swimming. D: By surfing the Internet.
The answer to this question is:
A