When storing compressed and liquefied gases, what precaution helps prevent ignition sources?

• A. Cylinders shall be purged, once empty.
• B. All cylinders, both full and empty, should be stored together to confine the hazard to a smaller area.
• C. Stored cylinders are secured so they cannot be knocked over.
• D. Empty cylinders should be removed from the premises immediately.

Answer: (C)