This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General surgery, Subject name: Surgery
In an adult, % of total body surface required to be involved in a burn injury to cause shock 
Select and explain. 
A. 15, B. 20, C. 25, D. 30
A: 15
Answer: A: 15 
Explanation: As the size approaches 10-15% of total body surface area (TBSA), the loss of intravascular fluid can cause a level of circulatory shock. Fuhermore, once the area increases to 25% of TBSA, the inflammatory reaction causes fluid loss in vessels remote from the burn injury.Ref: Bailey and love 27e pg: 619