What is urbanization?

the buildup of heat around large metropolitan centers

does movement of people from one country to another

the system of public works that support a city

the movement of people from rural areas to cities

Explanation:

You'd like to say it was C, but it really isn't. Some cities can't afford utilities while going through urbanization.

The technical definition is D.

The other two (A and B) are just wrong. That's not what it is.

answer; calendar;