What must be ensured to avoid obstruction in the seller’s warehouse regarding cylinders?

To avoid obstruction in the seller's warehouse concerning cylinders, ensuring egress is critical. Egress refers to the safe and unobstructed exit routes for personnel during emergencies or everyday operations. In the context of handling cylinders, maintaining clear egress pathways is vital not only for compliance with safety regulations but also to safeguard the wellbeing of all workers in case of an emergency. If egress routes are blocked, it can lead to hazardous situations where quick evacuation is needed, posing serious risks to safety.

The other options, while important in their own rights—such as transportation means for moving cylinders, inspection areas for checking the condition or safety of the cylinders, and personal space for workers—do not specifically address the critical need for keeping exit routes clear and accessible in a warehouse setting.