Which statement best describes graceful degradation in a resilient system?

• A. Graceful degradation means the system breaks immediately when any component fails.
• B. Graceful degradation means the system remains fully functional despite failures.
• C. Graceful degradation means the system continues to operate at reduced functionality when some components fail.
• D. Graceful degradation is unrelated to resilience.

Answer: (C)

Graceful degradation means the system keeps operating with reduced functionality when some parts fail. This approach preserves essential services instead of collapsing entirely, which is the essence of resilience. When a component or path fails, the system automatically limits noncritical features or switches to alternate, simpler behaviors so core operations remain available. For example, a web service might serve a reduced feature set or lower-quality output rather than going offline entirely, ensuring users can still accomplish the core task. The other ideas imply either a complete break, perfect continuity, or a disconnect from resilience concepts, which is why they don’t fit as well.