What indicates that an LP gas truck is designed for propane delivery?

The correct choice emphasizes the importance of color coding and labeling on an LP gas truck, which serves as a clear and immediate visual indicator that the truck is specifically designed for propane delivery. The color coding and labeling conventions are established industry standards that help ensure safety and proper handling. For example, many propane delivery trucks are painted in specific colors, often vibrant shades like yellow or red, and display labels or placards indicating hazardous materials—specifically propane—thus alerting both the driver and the public to the nature of the cargo.

In contrast, while the size of the truck may correlate with its payload capabilities, it does not uniquely identify the truck as being specifically for propane delivery, as trucks of various sizes can be repurposed for different types of cargo. Animatronics would not be relevant to the function of a propane delivery truck, as they pertain to entertainment or display rather than utility. Standard cargo holds can be found in many types of vehicles and do not designate any special capability or certification for gas delivery. Therefore, the labeling and color coding are critical safety features and identifiers that confirm the truck's purpose in handling LP gas.