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: Physiology
The only fixed cell of the connective tissue: 
Select and explain. 
A. Histiocyte, B. Lymphocyte, C. Neutrophils, D. Mast cell
A: Histiocyte
Answer: A: Histiocyte 
Explanation: None