Answer:
A. the rapid growth of cities
Step-by-step explanation:
Urbanization takes place when the number of people in an urban area increases. The urban areas refer to places with higher population density and vast human features in comparison to areas surrounding it. They are opposed to the rural areas which characterize for being farming or agricultural places. Cities are urban areas so their growth belong to the urbanization concept.
Urbanization is usually related to a modernization, industrialization, and/or rationalization.