Concept:Migration in Tropical Africa is mainly the movement of people from rural areas to urban centres.
Explanation:Rural-urban migration describes people leaving villages and farms to settle in towns and cities.
This movement is very common in Tropical African countries.
Urban areas attract people because they offer more jobs, schools, healthcare, and social amenities.
Rural areas often have poor farming conditions, low incomes, and limited basic infrastructure.
These factors push people away from the countryside and pull them toward the cities.
Therefore, the most frequent migration pattern in the region is from rural settlements to urban settlements.
Answer:D. rural-urban migration