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
Which is the MOST common surgically repairable cause of hyperparathyroidism? 
Select and explain. 
A. Adenoma, B. Carcinoma, C. Hyperplasia, D. Renal disease
A: Adenoma
Answer: A: Adenoma 
Explanation: Primary hyperparathyroidism is a surgical disease and operation is required for the hyperfunctioning gland. A single hyperfunctioning adenoma accounts for approximately 80% cases. Multiple adenoma or hyperplasia account for 15-20% and parathyroid carcinoma account for 1% cases of hyperparathyroidism.