This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Immunology, Subject name: Microbiology
[{'content': "Primary complex of TB is known as: \nSelect and explain. \nA. Ranke's complex, B. Ghon's complex, C. Assman focus, D. Simon's focus", 'role': 'user'}, {'content': "Answer: B \nExplanation: Ans. B. Ghon's complexPrimary focus - Ghon's focus + lymph nodes - Ghon's primary complex + calcification - Ranke's complex. Reactivation secondary TB - Simon's focus + calcification - Assman's focus", 'role': 'assistant'}]