What topographical feature indicates a city in Class C airspace?

In the context of Class C airspace, a city is typically indicated by the use of yellow topography on aeronautical charts. This color coding is specifically used to highlight areas that contain urban environments, which helps pilots quickly identify the locations of major cities when navigating. This visual cue is crucial for situational awareness, especially in busy airspaces where urban development might influence flight operations and altitude considerations.

In contrast, other features are not used to specifically indicate cities. Green shading generally denotes areas of lighter terrain and other topographical details. Contour lines represent elevation changes and landforms but do not specifically indicate city locations. Grid patterns are not common identifiers on aeronautical charts and serve different functions in mapping and navigation data. Thus, yellow topography is the most appropriate indicator for cities in the context of Class C airspace.