Which statement is true of megacities or trends in population?

A$.$ The majority of people still live in rural and suburban areas around the world.

B$.$ The United Nations defines a megacity as a metropolitan area with a total population of more than $5$ million people.

C$.$ Research shows that by the year $2030$ three out of five people will live in cities.

D$.$ Research indicates that by $2030,$ more people will live in rural and suburban areas than in cities.

E$.$ By the U$.$N$.$ definition, as of the year $2011,$ there were more than $50$ megacities in the world.