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: Pathology
Which of the following conditions are associated with pauci-immune crescenteric glomerulonephritis? 
Select and explain. 
A. Henoch-schonlein nephritis, B. Lupus nephritis, C. Microscopic polyangitis, D. Alpo's syndrome
C: Microscopic polyangitis
Answer: C: Microscopic polyangitis 
Explanation: Ans. is 'c' i.e., Microscopic polyangitis