This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General physiology, Subject name: Physiology
Most potent pain producing neurotransmitter 
Select and explain. 
A. Acetylcholine, B. Substance P, C. Bradykinin, D. Histamine
C: Bradykinin
Answer: C: Bradykinin 
Explanation: Algogens are pain producing substances and Bradykinin is the most potent algogen Ref:Guyton and Hall textbook of medical physiology 12th edition,page number:698,699,700