Final answer:
Gas cylinders must be properly secured by being chained to prevent accidents. Securing cylinders prevents them from falling and causing hazards.
Step-by-step explanation:
The correct answer to the question 'Make sure gas cylinders are _____________ or otherwise secured in place against a wall or on a cart.' is: d) Chained. Gas cylinders need to be safely secured to prevent them from falling over, which can lead to dangerous accidents. Securing them with chains is a common and secure method of ensuring they remain stationary and safe. It's also essential to follow all safety guidelines when handling gas cylinders, including keeping them upright and in a well-ventilated area away from sources of heat or ignition.