Two or more cylinders are connected in line in an oxyacetylene system.

• A. Manifold system
• B. Regulator
• C. Adjusting screw
• D. Needle valve

Answer: (A)

When two or more cylinders are connected in line in an oxyacetylene system, the arrangement is a manifold system. A manifold is a network of tubing and valves that ties multiple gas cylinders to a common distribution line, allowing gas from any cylinder (or several) to feed through to the regulator and torch. This setup enables continuity of supply, easier cylinder switching, and centralized control, which is essential when using multiple cylinders in parallel.

The other items describe individual components rather than an arrangement of multiple cylinders. A regulator reduces the high cylinder pressure to a usable level for safe welding. An adjusting screw is part of the regulator to set the outlet pressure. A needle valve provides fine control of gas flow, typically near the torch, but does not describe linking multiple cylinders together.