Which offense applies to a person who possesses an unauthenticated firearm in a public place?

The offense that applies to a person who possesses an unauthenticated firearm in a public place is unlawful possession of a firearm. This is because possessing a firearm that does not have proper documentation or authentication violates legal standards set for firearm ownership and use.

In many jurisdictions, individuals are required to possess firearms that are verified and properly licensed to ensure they are not stolen or unregistered. When someone is found with an unauthenticated firearm, it raises concerns about legality and proper ownership, leading to the designation of unlawful possession.

In contrast, the other options involve specific circumstances that do not align with the scenario presented. Carrying a prohibited weapon pertains to items that are outright banned or restricted, possession by a felon involves former criminals who may not legally own any firearms, and "none" does not apply because unlawful possession is indeed relevant in this case. Thus, the most fitting description of the offense committed by possessing an unauthenticated firearm is unlawful possession of a firearm.