Concept training for this debate

What is the primary function of the Geographic Names Information System (GNIS) in the context of US domestic mapping?

• A.To provide real-time GPS routing and satellite imagery for civilian navigation systems.
• B.To establish and maintain legal property boundaries and zoning districts for state and local tax assessments.
• C.To serve as the official federal repository for standardizing geographic feature names across all government maps and documents.
• D.To monitor and record topographical elevation changes caused by seismic and volcanic activity.