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: Microbiology
[{'content': 'Ricketsial infections cause 30% moality due to: \nSelect and explain. \nA. Endothelial injury, B. Hemodynamic instability, C. Endocarditis, D. Renal failure', 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. is. 'a' i. e., Endothelial injury", 'role': 'assistant'}]