Which of the following best describes "open transport" of firearms according to state law?

The description of "open transport" of firearms according to state law is best captured by the idea that the firearm is fully visible and unloaded. This definition aligns with the principles of open carry laws, which often stipulate that firearms must be conspicuously displayed rather than concealed. Open transport typically implies that the firearm is not only visible but also accessible, allowing law enforcement and the public to see that the weapon is being carried without obfuscation.

In many jurisdictions, the requirement for the firearm to be unloaded can also serve to enhance public safety, reducing the perceived threat when a firearm is visible in a non-concealed manner. This approach helps maintain transparency in the ownership and carrying of firearms in public spaces.

The other options do not accurately represent the notion of open transport as they involve concealment or restrictions that contradict the definition. For instance, hiding a firearm in a secure lockbox or carrying it in a separate bag does not fulfill the requirement of being fully visible. Additionally, while carrying multiple firearms might not inherently violate the principles of open transport, the crucial factor remains their visibility and state (loaded or unloaded), which is not emphasized in the other choices provided.