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

A．careless about his appearance
B．witty and eloquent
C．an inspiring professor
D．an absent-minded person

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