This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Oral cavity, Subject name: Surgery
[{'content': 'Trismus in oral cancer patients is severe in those treated with: \nSelect and explain. \nA. Surgery and Radiotherapy, B. Chemotherapy alone, C. Surgery alone, D. Not related to treatment', 'role': 'user'}, {'content': 'Answer: A \nExplanation: TRISMUS Restriction to mouth opening, including restrictions caused by trauma, surgery or radiation. Implications: Reduced nutrition due to impaired mastication, difficulty in speaking, and compromised oral hygiene. Limited jaw mobility can result from trauma, surgery, radiation treatment, or even TMJ problems. Radiation that affects the temporomandibular joint, the pterygoid muscles, or the masseter muscle. Secondary to scarring and edema after surgery.', 'role': 'assistant'}]