What shape is required for most hazardous-material package labels?
Correct answer: C – Diamond, or square-on-point
Hazard warning labels on most hazardous-material packages are square-on-point, commonly described as diamond-shaped. Their colors, symbols, and wording identify the applicable hazard. The label’s standardized shape helps drivers, handlers, and emergency responders recognize hazardous-material packages quickly.
Source: New Hampshire Commercial Driver’s License Manual — § 9.3.2, “Package Labels”, 49 CFR § 172.407(a) — Label specifications

