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
Tumorgenesis in Aging is due to: 
Select and explain. 
A. Telomerase reactivation, B. Telomerase inactivation, C. Increased apoptosis, D. Suppression of proto-oncogenes
A: Telomerase reactivation
Answer: A: Telomerase reactivation 
Explanation: Telomerase reactivation