A century ago, how many lived to, or past 100, within a population of 5 million

A．the aged should not go to the nursing home
B．we can lengthen our lives through high-tech medicine
C．centenarians die faster than those who are younger
D．the ever-growing segment of centenarians has caused concern

A．many of them had lived independently until their early 90s
B．they enjoy better health than people in their 70s
C．their longevity could be attributed to heredity
D．their medical expenditures are surprisingly low