Final answer:
Hazard Class 3 in the UN/DOT marking system includes flammable liquids such as gasoline, ethanol, and diesel fuel.
Step-by-step explanation:
In the UN/DOT marking systems, hazard Class 3 includes substances that are flammable liquids. Some examples of Class 3 substances are gasoline, ethanol, methanol, diesel fuel, and kerosene. These substances have a flash point below 93°C (200°F) and a boiling point of 35°C (95°F) or higher.