单选题：Old And Active It is well—known that life expectancy is long

Old And Active
It is well—known that life expectancy is longer in Japan than in most other countries. A 51 report also shows that Japan has the longest health expectancy in the world．A healthy long life is the result of the 52 in social environment.
Scientists are trying to work 53 exactly what keeps elderly Japanese people so healthy, and whether there is a lesson to be 54 from their lifestyles for the rest of us. Should we 55 any changes to our eating habits, for instance, or go jogging each day before breakfast? Is there some secret ingredient is the Japanese diet 56 is particularly beneficial 57 the human body?
Another factor contributing to the rapid population aging in Japan is a 58 in birthrate．Although longer 59 should be celebrated, it is actually considered a social problem．The 60 of older people had doubled in the last half century and that has increased pension and medical costs．The country could soon be 61 an economic problem, if there are so many old people to be looked 62 and relatively few younger people working and paying taxes to support them．
63 the retirement age from 65 to 70 could be one solution to the problem. Work can give the elderly a 64 of responsibility and mission in life. It’s important that the elderly play active 65 in the society and live in harmony with all generations.
A．late
B．modern
C．recent
D．last