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
Type of T-lymphocyte responsible for histocompatibility reaction is - 
Select and explain. 
A. Suppressor T-cell, B. Activator T-cell, C. Effector T-cell, D. Helper T-cell
D: Helper T-cell
Answer: D: Helper T-cell 
Explanation: None