The population between the age of 25 and 44 increased by 28.1%from 1980 to 1989 because()
A:this was the period of large inflow of young immigrants
B:this was the birth age of the baby boomers.
C:the large number born during WW II reached this age bracket
D:those who were born in the period of baby boom reached this age bracket
出自:00522《英语国家概况》