This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Parathyroid and adrenal glands, Subject name: Surgery
Most prevalent incidentaloma is: 
Select and explain. 
A. Cushing's adenoma, B. Pheochromocytoma, C. Adrenocoical carcinoma, D. Non-functioning adenoma
D: Non-functioning adenoma
Answer: D: Non-functioning adenoma 
Explanation: Adrenal Incidentaloma- - Incidentally detected adrenal mass through imaging performed for unrelated disease Nonfunctioning adenoma - 82% of incidentalomas Preclinical cushing - 5% Pheochromocytoma - 5% Adrenocoical Ca - 5% Metastatic Ca - 2% Aldosterone producing adenoma - 1%