Given the question: Read the article and select the best answer. Article: Are _ born or made? In my case it was definitely made. In my early 20s, I hardly went to bed before midnight, and I would always get up late the next morning. But after a while I couldn't ignore the high relationship between success and rising early. On those rare occasions where I did get up early, I noticed that my productivity was always higher. So I set out to become a habitual early riser. But whenever my alarm went off, my first thought was always to stop that noise and go back to sleep. Eventually some sleep research showed that my strategy was wrong. The most common wrong strategy is this: supposing you're going to get up earlier, you'd better go to bed earlier. It sounds very reasonable, but will usually fail. There are two main schools of thought on sleep patterns. One is that you should go to bed and get up at the same time every day. The second school says you should go to bed when you're tired and get up when you naturally wake up. However, I have found both are wrong if you care about productivity. If you sleep at fixed hours, you'll sometimes go to bed when you aren't sleepy enough. You're wasting time lying in bed awake. My solution is to combine both methods. I go to bed when I'm sleepy and get up with an alarm clock at a fixed time. So I always get up at the same time (in my case 5 a.m.), but I go to bed at different times every night. However, going to bed only when I'm sleepy, and getting up at a fixed time every morning are my ways. If you want to become an early riser, you can try your own. Question: Why did the author want to become a habitual early riser? Options: A: Because he / she wanted to have more sleep time. B: Because he / she wanted to do morning exercise. C: Because he / she wanted to test which school is better. D: Because he / she found that the productivity was higher.
The answer is:
D