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
Which of the following is not true about Gastrointestinal Stromal Tumor (GIST)? 
Select and explain. 
A. Originates from interstitial cells of Cajal, B. Most common mesenchymal tumour of gastrointestinal tract, C. Prognosis depends on size, D. ALK gene mutation is seen in most of the cases
D: ALK gene mutation is seen in most of the cases
Answer: D: ALK gene mutation is seen in most of the cases 
Explanation: Ans. d. ALK gene mutation is seen in most of the cases