In the post-industrial era, what is an edge city ?

In the post-industrial era, an edge city is a city or residential suburb that has shopping malls, business centres and entertainment centres which lies just outside the outskirt of the main residential area. This is actually an American term. These buildings fall mainly along the main traffic route. The edge city may be a semi urban area or a recently created development for business dealings and other entertainment places. This kind of city added a new dimension in the life of people.

Dall of the above all of the choices make sense