This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Physiology
[{'content': 'what is the diagnosis of the above pressure volume graph ? \nSelect and explain. \nA. mitral stenosis, B. mitral regurgitation, C. aoic stenosis, D. normal', 'role': 'user'}, {'content': 'Answer: B \nExplanation: ref : guyton and hall', 'role': 'assistant'}]