This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Hallmarks of Cancer, Subject name: Pathology
Gene associated with medullary carcinoma of thyroid is? 
Select and explain. 
A. RAS, B. RET, C. p53, D. MET
B: RET
Answer: B: RET 
Explanation: ANSWER: (B) RETREF: Schwartz's Principles of Surgery 9th edition chapter 38, Sabiston 18th ed chapter 36