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: Pathology
Delayed prolonged bleeding is caused by - 
Select and explain. 
A. Histamine, B. Leukocyte dependent injury, C. IL-1, D. Direct injury to endothelial cells
D: Direct injury to endothelial cells
Answer: D: Direct injury to endothelial cells 
Explanation: Ans. is `d' i.e., Direct injury to endothelial cellso Delayed prolonged leakage is caused either by the direct effect of injurious agent or by cytokine mediated endothelial retraction.