Globally, the Term "City

Globally, the term "city"

A) has no standard definition
B) describes a place with a population density of at least 1,000 people per square kilometer
C) describes a local government entity that provides basic services for its residents, including clean water, and can levy taxes for these purposes
D) describes a place that has a distinct physical boundary around it rooted in geological formations (such as a river, a mountain, or a desert) that limits its expansion in at least two directions