Final answer:
A viral infection can trigger an inflammatory response in the body, causing redness, warmth, and pain in the affected area.
Step-by-step explanation:
The answer is b) Viral infection. When a viral infection occurs, it can trigger an inflammatory response in the body. Inflammation is the body's response to infections or injuries, and it is characterized by redness, warmth, and pain in the affected area. When a viral infection is detected, the body releases chemicals that cause blood vessels to dilate, increase blood flow, and attract white blood cells to the infected area to fight off the infection.