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
"Nitroblue Tetrazolium Test" is used for: 
Select and explain. 
A. Phagocytosis, B. Complement, C. T cell, D. B cell
A: Phagocytosis
Answer: A: Phagocytosis 
Explanation: Phagocytosis