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: Pathology
[{'content': "Aphthous ulcers known as - \nSelect and explain. \nA. Canker sores, B. Marjolin's ulcer, C. Curling's ulcer, D. Cushing ulcers", 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. is 'a' i.e., Canker SoresAphahous ulcers o Also known as Canker Soreso These are superficial Ulcerations of oral mucosa.o The lesions may be Single or multiple.o Ulceration is surrounded by an erythematous halo and is Covered by a thin exudate.", 'role': 'assistant'}]