Cities together with their suburbs and population of more than 10 million people are called ___________.

Megalopolis

The correct answer is Option (3) → Megalopolis

A mega city or megalopolis is a general term for cities together with their suburbs with a population of more than 10 million people. New York was the first to attain the status of a mega city by 1950 with a total population of about 12.5 million. The number of mega cities is now 31. The number of mega cities has increased in the developing countries during the last 50 years vis-à-vis the developed countries.