This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Head & Neck, Subject name: Pathology
[{'content': 'Most important indicator of malignancy in smooth muscle tumors is: \nSelect and explain. \nA. Mitotic index, B. Atypia, C. Necrosis, D. Cellularity', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. (a) Mitotic index(Ref: Robbins 9th/pg 1223)Indicator of malignancy in soft tissue tumors (Leiomyosarcoma): Mitotic index Q > Atypia > Necrosis.', 'role': 'assistant'}]