This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Surgery
If GCS score is 8, head injury is classified as: 
Select and explain. 
A. Mild, B. Moderate, C. Severe, D. Very severe
C: Severe
Answer: C: Severe 
Explanation: Head injury can be classified as mild, moderate, or severe. For patients with a history of head trauma, classification is as follows: severe head injury if the GCS score is 3 to 8, moderate head injury if the GCS score is 9 to 12, and mild head injury if the GCS score is 13 to 15. Ref: Schwaz's principle of surgery 9th edition, chapter 42.