Final answer:
C) Blue Diamond. CNG labels are standardized with a blue diamond, which is part of the Hazchem code used for the safe handling of hazardous materials, indicating the risks associated with natural gas.
Step-by-step explanation:
The CNG label is standardized as a blue diamond with the words CNG, LNG, or un-odorized CNG within the diamond. This is part of a globally recognized labeling system known as the ‘Hazchem code’ or the ‘hazardous chemical code,’ which is used to indicate the type of hazard a chemical poses. This system is crucial for the safety handling and transportation of hazardous materials. In the context of CNG (Compressed Natural Gas) and LNG (Liquefied Natural Gas), the blue diamond is important for emergency responders as it provides quick visual communication of the risks associated with the materials, espicially since these gases are highly flammable. The coloring and signage are designed to be easy to understand at a glance in case of an emergency situation.