What equipment is needed for testing cartridge-operated extinguishers?

The correct choice highlights the essential equipment required for testing cartridge-operated extinguishers. Cartridge-operated extinguishers rely on gas cartridges to expel the extinguishing agent. To test these, a protective cage is necessary to safely secure the extinguisher during the testing process, preventing any accidents or injuries. The test pump, on the other hand, is critical for pressurizing the extinguisher during the test to ensure it operates correctly and safely under pressure.

While other options include equipment that may be relevant in different contexts, they do not encompass the specific needs for testing cartridge-operated extinguishers. For instance, a pressure gauge and hose could be useful for measuring or delivering pressure but are not specifically designed for the comprehensive and safety-focused requirements of testing cartridge-operated units. Similarly, the test wheel and measurement tape would not address the functional testing of the extinguishers, and while a hydrostatic testing kit is vital for testing certain types of extinguishers, it is not required specifically for cartridge-operated extinguishers. Thus, the choice accurately represents the specific tools and safety measures needed in this testing scenario.