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: Anatomy
[{'content': 'Which of the most commonest organ involved in sarcoidosis \nSelect and explain. \nA. Lung, B. Liver, C. CNS, D. Eye', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Presentation of sarcoidosis * Asymptomatic: abnormal routine chest X-ray (~30%) or abnormal liver function tests * Respiratory and constitutional symptoms (20-30%) * Erythema nodosum and ahralgia (20-30%) * Ocular symptoms (5-10%) * Skin sarcoid (including lupus pernio) (5%) * Superficial lymphadenopathy (5%) * Other (1%), e.g. hypercalcaemia, diabetes insipidus, cranial nerve palsies, cardiac arrhythmias, nephrocalcinosis Lung involvement occurs in >90% of sarcoidosis patients Ref Harrison 19th edition pg 2206', 'role': 'assistant'}]