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
Indication for surgery in a case of adrenal incidentaloma - 
Select and explain. 
A. Size > 5 cm, B. Bilateral adrenal metastasis, C. Functional tumor, D. All of the above
D: All of the above
Answer: D: All of the above 
Explanation: According to CSDT nonfunctioning adrenal tumors larger than 5 cm in diameter should be removed because of the high risk of malignancy.