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
[{'content': 'Which is the most specific marker for GIST \nSelect and explain. \nA. CD 117, B. CD 34, C. DOG 1, D. PDGF alfa mutation', 'role': 'user'}, {'content': 'Answer: C \nExplanation: CD117 is also known as CKIT is present in 90% of cases', 'role': 'assistant'}]