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
[{'content': 'Tumour associated with primary aldosteronism - \nSelect and explain. \nA. Adrenal adenoma, B. Adrenal hyperplasia, C. Von Hippel-Lindau syndrome, D. Adrenal carcinoma', 'role': 'user'}, {'content': 'Answer: A \nExplanation: in most cases involve unilateral adenoma which is usually sma and may occur on either side( Harrison 17 pg 2260 )', 'role': 'assistant'}]