Which of the following places is it illegal to carry a concealed firearm in Montana without a proper permit?

The correct answer is D. All of the above. In Montana, it is illegal to carry a concealed firearm in National Parks, banks, and government buildings without a proper permit. While some states may have different laws regarding carrying concealed firearms in certain places, Montana has strict regulations in place to ensure safety and security in these locations. Therefore, options A, B, and C are incorrect as they each refer to individual places where it is illegal to carry a concealed firearm without a permit, while option D encompasses all of these locations.