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: Microbiology
C1 esterase inhibitor deficiency causes ? 
Select and explain. 
A. Neisseria infection, B. Hereditary angioneurotic edema, C. Hemolytic disease, D. Hemolytic uremic syndrome
B: Hereditary angioneurotic edema
Answer: B: Hereditary angioneurotic edema 
Explanation: Ans. is 'b' i.e., Hereditary angioneurotic edema Hereditary angioneurotic edema is due to C1 inhibitor (CI esterase inhibitor) deficiency.