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
Factitious hyperinsulinemia is differentiated from insulinoma by- 
Select and explain. 
A. C- peptides, B. Insulin antibodies, C. Serum glucose level, D. None of the above
A: C- peptides
Answer: A: C- peptides 
Explanation: None