This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Myocardial Infarction, Subject name: Pathology
[{'content': "Which of the following causes 'no-reflow' phenomenon in acute myocardial infarction contributing to reperfusion injury? \nSelect and explain. \nA. Myocyte hypercontracture:, B. Leucocyte aggregation, C. Free radicals, D. Complement activation", 'role': 'user'}, {'content': 'Answer: B \nExplanation: Factors that contribute to reperfusion injury in myocardial infarction include the following: Mitochondrial dysfunction Myocyte hypercontracture Free radicals Platelet and complement activation Leukocyte aggregation - may occlude the microvasculature and contribute to the "no-reflow" phenomenon.', 'role': 'assistant'}]