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
All are involved in MEN type II A except 
Select and explain. 
A. Parathyroid, B. Adrenal, C. Thyroid, D. Pituitary
D: Pituitary
Answer: D: Pituitary 
Explanation: None