This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Endocrinology, Subject name: Medicine
All are TRUE about hyperparathyroidism, except- 
Select and explain. 
A. Commonly occurs after thyroidectomy, B. May cause hypercalcemia, C. Solitary adenoma is the most common cause, D. None of the above
D: None of the above
Answer: D: None of the above 
Explanation: solitary adenoma is the most common cause ( Harrison 17 pg 2380)