Read the article and select the best answer. Article: HIGH (Human Growth Hormone) could be the favorite drug at the next athletic world championships, and we might never know it. It is a natural substance produced by the human body, and it helps children's bones and muscles to grow. Scientists are allowed to make the drug and it is also legal to take HGH in most countries. HGH is considered a wonder drug for children. It helps many children with growth problems every year. However, some athletes are now taking the drug. HGH helps add muscle in adults and recent research by the World Anti-Doping Agency shows that HGH may improve the sportsman's time by 5% when he takes part in short, fast races. Some athletes say that HGH surely makes them stronger. It also helps them to recover more quickly from injuries. Although it is _ by most professional sports, HGH is almost impossible to test for. The drug is completely natural and it will only show in tests for around 24 hours after taking it. Testing is usually done only during competitions, but athletes use HGH during training, so it is very difficult to know who has used the drug. This makes it very attractive for some athletes. Scientists are developing a new test which will find the drug in the body for up to two weeks. But it isn't going to be easy. Everybody has different levels of natural HGH in their body. For this reason, scientists are warning athletes of the possible problems with the drug. Research shows that HGH increase the risk of cancer. But is this enough to stop athletes from taking it? Scientists don't think so. Some athletes will do all they can to win, and worry about their health later. Question: Besides making them stronger, why is taking HGH attractive for some athletes? Options: A: Because it can be taken during a competition. B: Because it is very difficult to test. C: Because it is allowed to take it. D: Because it works for 24 hours.
A:
B