Final answer:
The main objective of the audit is to ensure that environmental protection and alarm devices are functioning correctly, as their primary role is to safeguard environmental compliance. Hence, option (B) is correct.
Step-by-step explanation:
The most significant objective of an internal audit of environmental protection and alarm devices is to determine whether (option B) The devices are installed and operating properly. This is because the primary purpose of such devices is to ensure the safety and compliance of the organization with environmental regulations and policies.
While other factors like the completeness of device specification documents, authorization of acquisitions and disposals, and proper recording of costs are also important, they serve as supporting elements to the main function of the devices which is protecting the environment as well as alerting to any potential issues or failures.