Answer:
B. grow exponentially
Step-by-step explanation:
When countries become richer, services aimed at the population and offered by governments have more quality, which provides a high quality of life for the population.
When a country gets rich, the unemployment rate decreases, health services are faster and more efficient, the country's economy improves, people get better housing, basic sanitation, education and many other improvements. As a result, people tend to have more children, and these children are better able to survive until they have their own children. As a result, the population growth rate grows.
We can say that this is an exponential growth, since as the population grows from the growth of the country's wealth.