This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Pathology
Which of the following markers is specific for gastro intestinal stromal /tumors (GIST)? 
Select and explain. 
A. CD 117, B. CD34, C. CD23, D. S-100
A: CD 117
Answer: A: CD 117 
Explanation: Marker in GIST CD117-( c-kit)- 95% CD34-70% Smooth muscle Actin-5%