Final answer:
B) African countries are in the middle stage of demographic transition, which is characterized by high birth rates and declining death rates, leading to rapid population growth.
Step-by-step explanation:
The middle (high growth) stage of demographic transition is typically characterized by a decline in death rates due to improvements in healthcare and nutrition, while birth rates remain high; this results in rapid population growth.
When analyzing different world regions in the context of the demographic transition model, b) African countries fit this description as they are currently experiencing high birth rates coupled with decreasing death rates.
There are four stages in demographic transition, with the second stage being characterized by high growth.
European countries, North American countries, and other economically developed countries have typically moved beyond this stage into later stages where growth rates have slowed down due to lower birth rates.
It's clear that African countries are in the middle stage of demographic transition, given the current population patterns and the presence of countries like Angola, which exhibits a wide base in its population pyramid indicative of high birth rates.