19. When an incident occurs or threatens, local emergency personnel manage response using NiMS principles and ics. If the incident is or becomes large or complex, A. Federal authorities assist. B. Mutual Aid Agreements are executed. C. A Unified Command is established. D. Local EOCs activate.

To solve this problem, we need to identify the correct answer based on the principles of the National Incident Management System (NIMS) and the Incident Command System (ICS) in emergency management. 1. **Understanding the context**: The question states that when an incident is large or complex, certain actions or responses are taken by emergency personnel. 2. **Analyzing the options**: - **A. Federal authorities assist.**: This is a possibility, but it is not the primary action taken when an incident becomes large or complex. - **B. Mutual Aid Agreements are executed.**: This can happen, but it is not the most direct response to a large or complex incident. - **C. A Unified Command is established.**: This is a key principle of NIMS and ICS, especially for managing large or complex incidents involving multiple agencies. - **D. Local EOCs activate.**: While this can occur, it is not the primary response to the complexity of an incident. 3. **Conclusion**: The most appropriate response when an incident is or becomes large or complex is the establishment of a Unified Command, as it allows for coordinated management across different agencies and jurisdictions. Therefore, the correct answer is **C. A Unified Command is established.**