What must be clearly labeled on a poison to sell it legally?

The requirement for the labeling of poisons is established to ensure consumer safety and promote proper handling and usage of such hazardous substances. The presence of the word "poison" on the label is critical because it directly communicates the potential dangers associated with the substance. This clear labeling helps inform users or handlers of the risks involved, enabling them to take appropriate precautions.

This regulatory stipulation aims to prevent accidental ingestion or misuse of toxic substances, ensuring that anyone who comes into contact with the product understands it as a serious health risk. In labeling regulations, clarity and directness are vital, thus making the explicit term "poison" the correct answer in identifying what must be clearly labeled for legal sale in many jurisdictions, including Minnesota.