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': 'Which one of the following is the most common initial symtoms of byssinosis - \nSelect and explain. \nA. Chest tightness, B. Wheezing, C. Cough, D. Haemoptysis', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]