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
A patient with long-standing multinodular goitre develops hoarseness of voice; also, the swelling undergoes a sudden increase in size. Likely diagnosis is 
Select and explain. 
A. Follicular ca, B. Papillary ca, C. Medullary ca, D. Anaplastic ca
A: Follicular ca
Answer: A: Follicular ca 
Explanation: History of sudden growth in a long-standing goitre and hoarseness are suggestive of malignant change.
Most common carcinoma to develop in developing in long-standing multinodular goitre is Follicular carcinoma.