This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Respiratory system, Subject name: Medicine
[{'content': 'Which of the following is false about hemoptysis \nSelect and explain. \nA. Massive hemoptysis is bleeding >200-600 cc in 24 hours, B. In 90% cases, bleeding from brochial aeries, C. CT chest is the first investigation done, D. In an unstable, rigid bronchoscopy is done to identify the lesion.', 'role': 'user'}, {'content': "Answer: C \nExplanation: Massive hemoptysis is variably defined as hemoptysis of greater than 200-600 cc in 24 hrs.The most common site of hemoptysis is bleeding from bronchial aeries of small-to medium-sized airways.The first investigation of choice is a standard chest radiograph.If a source of bleeding is not identified on plain film,a CT of the chest should be obtained.In unstable patients,rigid bronchoscopy can be done to visualise the endobronchial lesions. Reference:Harrison's medicine-18th edition,page no:285.", 'role': 'assistant'}]