阅读下列材料，从A、B、C、D四个选项中选出最佳答案。
As we are getting older and older, our ability to think and remember starts to become worse.
But not everyone is like this. Some people are super-agers, who are over the age of 80, but have the brain of much younger people.
Scientists know that parts of the brain become smaller in size with age. But the change of the super-agers' goes much more slowly. In her recent study, Emily Rogalski, a neuroscientist (神经科学家), showed that super-agers have young brains. The area of the brain for attention and memory (记忆) was shown to be thicker in super-agers. "When we look at a super-ager's brain, we see that it looks more like a 50-year-old brain than an 80-year-old one".
Scientists say super-agers have several things in common, including an active lifestyle. Most of them like travelling and playing sports. They always enjoy reading. They usually have healthy relationships and spend time with friends.
"Growing old, she adds," does not have to be depressing (令人沮丧的) and sad. Perhaps, if we expect a little better from ourselves, we'll understand that not all getting old makes us sad".
Rogalski said jokingly that super-agers do not grow on trees- meaning they are special and few. She says she wants to find out why a super-ager's mind is working so well and not getting old as quickly as most. The science behind super-agers is a new, but growing field. It attracts many scientists. Scientists in the research offer the advice to us: Stay active. Learn new things. Challenge yourself. Develop healthy relationships.