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
Commonest presenting complaints of medullary carcinoma thyroid - 
Select and explain. 
A. Diarrhoea, B. Dysphagia, C. Hoarsness, D. Flushing
A: Diarrhoea
Answer: A: Diarrhoea 
Explanation: None