This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: G.I.T, Subject name: Anatomy
[{'content': 'Most appropriate marker of GIST \nSelect and explain. \nA. CD 117, B. CD 34, C. CD 23, D. S-100', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Refer Robbins page no 789-790 Cd117 is the most impoant diagnostic marker is detectable in 95 percnt of the patients', 'role': 'assistant'}]