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: Physiology
Which of the following causes decrease in BP 
Select and explain. 
A. Thromboxane A2, B. Vasopressin, C. NO, D. PGF2
C: NO
Answer: C: NO 
Explanation: NOSubstances which cause vasodilatation can cause fall in BP.Substances which cause vasoconstriction can cause a rise in BP.Among the given options only NO (nitric acid) is vasodilator (causes fall in BP). Other three options cause vasoconstriction (cause rise in BP).