This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Thyroid and Parathyroid, Subject name: Pathology
Most common cause of primary hyperparathyroidism - 
Select and explain. 
A. Hyperplasia, B. Solitary'- Adenoma, C. Carcinoma, D. Multiple adenomas
B: Solitary'- Adenoma
Answer: B: Solitary'- Adenoma 
Explanation: Ans. is 'b' i.e., Adenoma Hyperparathyroidismo Hyperparathyroidism is caused by elevated parathyroid hormone.o Primary hyperparathyroidism : an autonomous overproduction of parathyroid hormone (PTH), usually resulting from an adenoma or hyperplasia of parathyroid tissue.HyperparathyroidismParathyroidadenoma(85%-95%)Primaryhypoplasia(5%-10%)Parathyroidcarcinoma(>]%)Note: The most common cause of primary hyperparathyroidism is a solitary parathyroid adenoma arising sporadically.