Which of the following is not one of the three basic container types listed (Cylinder, Tank, Line)?

• A. Cylinder
• B. Tank
• C. Line
• D. Drum

Answer: (D)

Knowing how to classify containers helps you quickly assess hazards at an incident. The three basic container types listed are cylinder, tank, and line, which cover portable high‑pressure vessels, large bulk containers, and piping systems. A drum, while common for storing liquids, is not part of that set—it’s a separate packaging type. Drums can carry various contents and present hazards, but they don’t fit the cylinder/tank/line categorization used for rapid hazard assessment, so they’re the correct choice as not belonging to the three basic container types.