A、The one who’s over 50. B、The one who’s over 90. C、The one who’s over 80. D、The one who’s over 100. D对话开头女士提到centenarian这个词，接着解

W: New studies are proving that more and more Americans are living way beyond their expectations when they get to their eighties or nineties and even into a second century.
M: Sounds very interesting.
W: So then, we decided to get a first-hand look into this incredible group of senior citizens—[6] the centenarians, individuals who are over 100. We decided to visit a unique village whose 150 elderly residents live independently in small apartments. Last June we spent a lovely sunny afternoon at Cherry Blossoms Village in Baltimore, Maryland. There we met with a few of the remarkable centenarians living there.
M: According to recent statistics, the number of centenarians is growing rapidly.
W: Yes, I just read some fascinating new research done by some scientists in Georgia who studied 96 independent centenarians. [7] They wanted to discover what the real secrets were to becoming an active and healthy 100-year-old. They were quite surprised by what they found. [8] Most people believe diet, exercise and genetics are the common threads among most centenarians. However, they were not among the traits that all of these individuals had in common.
M: OK, then, what were the common themes? What did the scientists find out?
W: Well, they uncovered four themes that all 96 of their centenarians had in common. These were optimism, engagement or commitment to something they were interested in, activity or mobility, and the strength to adapt to loss. All four of these themes were pervasive among the "oldest old" they studied.
M: I was told that there have centenarians living in that Baltimore village who have unconventional hobbies such as competitive swimming, auto racing, and horseback riding. Is this the norm?
W: Well... no, not exactly... not all of them take it quite this far, but all of our residents do some sort of regular physical activity.
M: And what about diet?
W: [9] They found that the centenarians they studied had the highest caloric intake and are the largest amount of fat.
M: Earlier you mentioned that the Georgian researchers found that [10] the ability to cope with loss is another characteristic that healthy centenarians share.
W: Yes, exactly! If you live to be 100 you are bound to lose a lot. It’s natural. Most of our centenarians have lost a spouse, children, and siblings. Many have lost their peer group as well. But in spite of this, they are able to incorporate that loss in a positive way so they can go on with their lives.
6.  What is a centenarian according to the conversation?
7.  What did the scientists in Georgia want to find out?
8.  What do most people believe to be the common threads among most centenarians?
9.  What did scientists in Georgia find about the centenarians’ diets?
10.  What characteristic of the centenarians is mentioned at the end of the conversation?