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: Medicine
[{'content': 'A female patient Chandani develops chest pain which is not associated with exercise and chest auscultation shows multiple non ejection clicks. The investigation which is used to diagnose the disease is - \nSelect and explain. \nA. Echocardiography, B. Pyrophosphate scan, C. Thallium 201scan, D. ECG', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]