Answer:
D. Stage 4.
Step-by-step explanation:
The Demographic Transition model was developed around the 1930-1940, to study the population changes in different countries, and how that relates to the industrial revolution.
In the first stage, there is high fertility, and high mortality. As the medicine gets better, there is a lower death rate on stage 2., and rapid population growth. On stage 3, birth rate decreases, due to access to contraception. And in Stage 4, There is low birth rate and mortality rate. Indicating low growth.