This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General anatomy, Subject name: Anatomy
Lewis triple response is caused due to 
Select and explain. 
A. Histamine, B. Axon reflex, C. Injury to endothelium, D. Increased permeability
A: Histamine
Answer: A: Histamine 
Explanation: Ref Goodman and Gilman 10/e p650 With injection of histamine there is triple response Red spot Wheal Flare