When a city has 10 million or more residents, it is a(n):

• A. Megaregion
• B. Megacity
• C. Metropolis
• D. Suburb

Answer: (B)

When a city's population reaches around 10 million, it is categorized as a megacity, signaling a scale of urban life characterized by dense population, complex infrastructure, and significant economic and cultural influence. The term megacity is specifically used for cities with populations of 10 million or more. In contrast, a megaregion refers to a large urbanized area that spans multiple cities and often includes cross-border economic and social networks, not a single city’s population. A metropolis is a large and influential city, but the designation isn't fixed at 10 million; some metropolises have fewer than 10 million inhabitants. A suburb is a residential area outside a central city, typically smaller and not considered a standalone megacity. Therefore, the city with 10 million or more residents fits the megacity label.