If birth rates fall below the replacement level, than a country is in which stage of demographic transition?

Fourth Stage

Explanation:

During the fourth stage of demographic transition, the birth rates with in a population fall below the level of replacement and thus the population of such countries starts shrinking. This was once a common scenario in countries like Japan, Italy and Germany. The economy sees a down fall as the ageing population increases with no replacement of it in near by future.

Mostly the developed nations after the post industrial age are  facing this situation.

your answer should be c) enjoy!