Which of the following statements about overcurrent protective devices is true?

The statement that overcurrent protective devices must adhere to specific product standards is accurate because these devices, such as circuit breakers and fuses, are designed to protect electrical circuits by interrupting current flow in case of overloads or short circuits. Adhering to standards ensures safety, reliability, and compatibility with existing electrical systems, which is crucial in preventing equipment failure and hazards, such as fire or electrical shock.

The other options are not accurate in the context of overcurrent protective devices. They are used across various applications, not solely residential settings, as indicated in the first option. The second option highlights the importance of adhering to product standards. Furthermore, overcurrent protective devices do not replace the need for transformers; instead, they serve a different function related to current protection. Lastly, they do not work solely based on voltage levels; their primary focus is on current flow and the potential for overload scenarios. Hence, B is the only statement that correctly reflects the role and requirements of overcurrent protective devices.