What type of materials might have restrictions on transportation due to safety concerns?

The option regarding explosives and poisonous gases correctly identifies materials that have significant restrictions on transportation due to their inherent dangers. Explosives are substances that can cause violent reactions when exposed to heat, friction, or other stimuli, making their transportation highly regulated to prevent accidents and ensure public safety. Poisonous gases pose risks of serious health hazards, including respiratory issues or toxicity to individuals who might be exposed during transport.

Regulatory agencies, such as the Department of Transportation (DOT) in the United States, impose strict guidelines and requirements for the handling, packaging, and transport of hazardous materials like explosives and toxic gases. These regulations ensure that the risk of accidents, leaks, or environmental contamination is minimized during transportation.

In contrast, non-hazardous materials generally do not carry the same level of risk and therefore are not subject to the same stringent regulations. Food products, while they may have guidelines for safe transportation to ensure quality and prevent contamination, do not typically fall under the category of hazardous materials. Household items usually also do not pose significant dangers that warrant strict transportation regulations, thus they are generally unrestricted in terms of transportation.