The correct answer is A) Restricted. Formic acid is a hazardous cargo that requires restricted gauging. This means the cargo tank must be equipped with closed gauging systems that limit the release of vapors to the atmosphere during the gauging process. Open gauging, which allows direct exposure to the atmosphere, is not permitted for hazardous cargoes like formic acid. Closed gauging, while more restrictive than open gauging, still does not provide the level of safety required for a cargo like formic acid, which is why restricted gauging is the appropriate method.