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: Pathology
Malignancy in pheochromocytoma is indicated by- 
Select and explain. 
A. Vascular invasion, B. Mitotic figures, C. Capsular invasion, D. metastasis
D: metastasis
Answer: D: metastasis 
Explanation: "Because malignant and benign pheochromocytomas may have an identical histological appearance, the only absolute criterion of malignancy is metastasis"
​"The diagnosis of malignant pheochromocytoma is made only when metastasis is demonstrated"