Given the question: Read the article and select the best answer. Article: Every day when Cora Castle, 14, from Indiana, US goes back home, she opens her computer and logs into a website called Fuel Up to Play 60. She puts on what she has eaten and what kind of activities she has played that day. Then the site decides whether Castle has eaten healthily and done enough exercise. All the seventh graders in Castle's school have done the same thing since the year started. It's part of their health class. If the site finds her habits are unhealthy, it will give her advice. If she does something good, the website will give her a star. Her health teacher set up a competition to see which student could get the most stars from the website. Castle has got 30 stars so far. Cameron Bartlett said she liked tracking the food and activities. "This is the first year we've done it," she said. "It's really interesting to see all of the different choices that we have." The seventh grade health class is coming to an end. They won't be in health class, but the students all said that they would go on to take part in the Fuel Up to Play 60. "There's lots of bad food out there that we've all been eating," Bartlett said "This really helps all of us eat healthier food." Question: The passage is mainly about a website for helping people _ . Options: A: win in competitions B: eat more healthy food C: do enough exercises D: have good living habits
The answer is:
D