What is the term used for a cardboard carton that houses a nuclear gauge in a Type A shipping case?

The term "overpack" refers to a type of shipping case designed to provide additional protection to the primary packaging of hazardous materials, such as a nuclear gauge. It encompasses the entire unit, including the inner contents, which in this case, would be the nuclear gauge itself housed in its own protective container. An overpack is typically used when the primary package may not withstand the rigors of transportation on its own or to provide an extra layer of isolation from the surroundings, ensuring safe handling and transport of the gauge.

The other terms used in the options refer to different aspects of shipping or packaging. "Container" generally signifies any type of vessel used to hold materials, while "package" is a broader term that includes both the container and any additional protective elements. "Carton" specifically denotes a box made from cardboard, which does not encompass the full protective intent or the structured shipping requirements of a Type A case. Thus, the term "overpack" is the most accurate designation for a cardboard carton housing a nuclear gauge in this specific shipping context.