What must be affixed to all corrugated ribbon containers?

The correct answer emphasizes the need to inform handlers that corrugated ribbon containers can conduct electricity. This is critical, especially in environments where electrical safety is a concern. Corrugated ribbon containers are often used for a variety of materials, some of which may be sensitive to electrical currents or may help in conducting electricity, potentially leading to safety hazards. By labeling these containers appropriately, it ensures that personnel handling these items are aware of the risk, which can help prevent accidents and promote safer handling practices.

The other warnings address different types of hazards that may not be specific to corrugated ribbon containers. For example, the warning about handling with care is generally applicable to many types of packaging but does not specifically relate to the unique characteristics of corrugated ribbon containers. Similarly, warnings about flammable materials or toxic substances would only be relevant if the contents were hazardous in that regard, which is not inherently true for all corrugated ribbon containers. Therefore, the emphasis on electrical conductivity is the most relevant and necessary caution in this context.