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
Calcitonin is a marker of which of the following? 
Select and explain. 
A. Pancreatic cancer, B. Lobular carcinoma of breast, C. Melanoma, D. Carcinoma of thyroid
D: Carcinoma of thyroid
Answer: D: Carcinoma of thyroid 
Explanation: Calcitonin level is elevated in medullary carcinoma of thyroid.