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': 'Most common symptom of lung carcinoma \nSelect and explain. \nA. Cough, B. Dyspnoea, C. Weight loss, D. Chest pain', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]