What is required to transport a firearm legally in a vehicle in Hawaii?

In Hawaii, it is required by law that when transporting a firearm in a vehicle, the firearm must be unloaded and locked in the trunk. This measure ensures that the firearm is securely stored and not readily accessible, thus promoting safety and preventing potential accidents. This requirement helps to minimize the risks associated with firearms while in transit. Therefore, option A is the correct choice.

Options B, C, and D are incorrect because they do not align with Hawaii's regulations for the legal transportation of firearms in a vehicle. Transporting a loaded firearm in the glove compartment or leaving the firearm visible on the passenger seat would not comply with the state's laws regarding firearm transportation. Additionally, having a carry permit does not exempt an individual from following the specific requirements related to firearm transport in Hawaii.