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: Medicine
Immune tolerance can be induced by- 
Select and explain. 
A. Excess antigen, B. Excess antibody, C. Excess complement level, D. Neonatal thymectomy
A: Excess antigen
Answer: A: Excess antigen 
Explanation: None