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
For which one of the following tumours Gastrin is a biochemical marker: 
Select and explain. 
A. Medullary carcinoma of thyroid, B. Pancreatic neuroendocrine tumour, C. Pheochromocytoma, D. Gastrointestinal stromal tumor
B: Pancreatic neuroendocrine tumour
Answer: B: Pancreatic neuroendocrine tumour 
Explanation: . Pancreatic neuroendocrine tumour