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
[{'content': 'Lines of Zahn occur in which of the following? \nSelect and explain. \nA. Postmortem clot, B. Infarct, C. Embolus, D. Coralline thrombus', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Thrombi often have grossly and microscopically apparent laminations called lines of Zahn; these represent pale platelet and fibrin deposits alternating with darker red cell–rich layers. Such laminations signify that a thrombus has formed in flowing blood; their presence can therefore distinguish antemortem thrombosis from the bland non laminated clots occurring in postmortem clots.\nIn veins, thrombi form coral-like system with framework of platelets, fibrin and trapped white blood cells; This is a coralline thrombus.', 'role': 'assistant'}]