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: Gynaecology & Obstetrics
[{'content': 'Which of the following is the rarest modification in a fibroid uterus : \nSelect and explain. \nA. Red degeneration, B. Calcification, C. Hyalinization, D. Sarcomatous changes', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Sarcomatous changes', 'role': 'assistant'}]