Which basic ladder components are spring-loaded, retractable, curved metal pieces?

The correct choice refers to roof hooks, which are essential components designed to assist firefighters when accessing roofs during operations. These roof hooks are typically spring-loaded and retractable, allowing them to be extended when needed and drawn back when not in use. Their curved design enables the hooks to secure the ladder to the edge of a roof, providing stability and prevention from slipping during firefighting operations or rescues from elevated areas.

Understanding the role of roof hooks is crucial for effective ladder usage in firefighting. They help ensure that the ladder remains securely in position, which is vital for safety when firefighters are working on inclines or unstable surfaces. Other components, such as rungs or tips, do not have the retractable feature and therefore would not fit the description provided. Rungs are stable and fixed to allow firefighters to climb, while tips usually refer to the ends of the ladder that may come into contact with the ground or wall, lacking a spring-loaded mechanism. Thus, roof hooks accurately fulfill the specified characteristics in the question.