Final answer:
The 2007 National Strategy for Health and Preparedness called for collaboration across all levels of government to ensure an effective response to health emergencies and disasters. Therefore, the correct option is A.
Step-by-step explanation:
The 2007 National Strategy for Health and Preparedness established five key principles, one of which called for collaboration across all levels of government. This principle emphasizes the importance of different government entities working together to achieve a coordinated and effective response to health emergencies and disasters. Collaboration ensures that the expertise and resources of federal, state, and local governments are effectively pooled to address public health challenges, including civil defense and emergency preparedness measures, which covers anti-terrorism legislation and ensuring the resilience of a critical national infrastructure.