A. You must have a Alabama conceal carry license.
B. The firearm must be out of sight at all times.
C. The vehicle must be locked when you leave or the firearm must be kept in a locked compartment inside the vehicle or in a locked container permanently attached to the vehicle (ie pickup bed tool box).
That is the correct answer. Except, Alabama doesn't issue concealed carry permits. They issue pistol permits. Also, pistol permits don't apply to long guns. The rule with long guns, on school grounds requires it to be hunting season and you having a hunting licence.
