"Japan has the most rapid and serious aging problem in the world due to declining fertility rates coupled with rising longevity. A contrarian view is that an aging society is not necessarily a serious problem if they experience 'healthy aging' because many elderly have the skills, experience and good attitude as workers or volunteers to continue playing an active and useful role in society. By 2007, 21% of the Japanese population was over 65 years old; by 2055, it is projected to be 40.5%. The nation is facing a looming demographic and fiscal crisis which cannot be resolved easily." According to the reading passage, Japan is at what stage in the Demographic Transition Model?

a) 1

b) 2

c) 3

d) 4