This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Blood Vessels, Subject name: Pathology
[{'content': 'Atherosclerosis causes fibroblast plaque formation by injury to? \nSelect and explain. \nA. Endothelium, B. Fibroblast, C. Macrophage, D. Smooth muscle cells', 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. (a) Endothelium(Ref: Robbins 9th/pg 498-499; 8th/pg 505; Harrison 18th/pg 1503)Pathogenesis of atherosclerosis best explained by the 'Response to Injury hypothesis to endothelium", 'role': 'assistant'}]