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': 'True regarding presentation of Primary TB is: \nSelect and explain. \nA. Bilateral pleural effusion with negative tuberculin test, B. Unilateral hilar lymphadenopathy, C. Sustained chronic pyrexia, D. B/L pleural effusion with positive tuberculin test', 'role': 'user'}, {'content': 'Answer: B \nExplanation: TB in young children is almost invariably accompanied by hilar or paratracheal lymphadenopathy due to the spread of bacilli from the lung parenchyma through lymphatic vessels.', 'role': 'assistant'}]