Write a multi-choice question for the following article, with the given choices and answer: Article: One of the tough things about being a high school student is that you never seem to get enough sleep at night, which often leaves you nodding off during classes. "The best amount of sleep to get is about seven and a half to eight hours," Peter Venn at Queen Victoria Hospital, UK, told The Telegraph. Spending either less than six or more than nine hours in sleeping puts your health at risk. A popular solution to a lack of sleep at night is to take a "power nap" during the day, but does this work? Generally speaking, it can be beneficial. Research shows that a nap in the middle of the day --even a brief one as short as five or 10 minutes ---can clear your mind and leave you with increased energy and improved productivity , according to Forbes. However, as refreshing as it might be, if you are getting adequate sleep at night, taking a power nap isn't such a wise choice. The reason is that sleeping during the day can interfere with your body's biorhythms . The brain gets used to going to bed at roughly the same time each night and getting up at the same time each day, and you don't want to disturb this routine. One more thing to keep in mind is that a power nap should never be used as a replacement for a good night's sleep. "Twenty minutes of power nap during the day is not like a tablet which will definitely work," Rahul Mukherjee, an Indian sleep specialist, told The Telegraph. "An hour's sleep before midnight is worth a couple of hours' sleep after midnight." Options: A Because it refreshes people and thus improves their productivity. B Because it is good for our body's biorhythms. C Because it takes little time but always works well. D Because it can be used as a replacement for a good night's sleep. Answer: A Because it refreshes people and thus improves their productivity. Question:
Why can taking a power nap in the middle of the day be beneficial?