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: Surgery
The expression of the following oncogene is associated with a high incidence of Medullary carcinomas of thyroid 
Select and explain. 
A. p53, B. Her 2 neu, C. Ret proto-oncogene, D. Rb gene
C: Ret proto-oncogene
Answer: C: Ret proto-oncogene 
Explanation: None