Which classes of goods are not permitted in excepted quantities?

The correct answer is based on the regulatory framework governing hazardous materials, specifically the guidelines established by the United Nations and applicable transport regulations. Classes of goods categorized as 1 and 7 relate to explosives and radioactive materials, respectively.

Explosive materials pose significant safety risks due to their nature and potential for causing harm if not managed correctly. As a result, they are subject to stringent regulations, thus they cannot be transported in excepted quantities, which are simplified methods of shipping certain lower-risk hazardous materials.

Similarly, radioactive materials (Class 7) are strictly regulated due to the health risks associated with radiation exposure. Their handling, packaging, and transport require special considerations that are not generally compatible with the excepted quantity provisions.

Overall, Classes 1 and 7 are considered too hazardous for transport under the exceptions that apply to other less dangerous goods. This understanding helps ensure safety and compliance in the transportation of potentially dangerous substances.