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 common site of GIST is \nSelect and explain. \nA. Stomach, B. Small intestine, C. Large intestine, D. Spleen', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Gastrointestinal Stromal Tumors Gastrointestinal stromal tumors (GISTs) are the most common sarcomatous tumors of the GI tract. Originally thought to be a type of smooth muscle sarcoma, they are now known to be a distinct tumor derived from the interstitial cells of Cajal, an intestinal pacemaker cell. They can appear anywhere within the GI tract, although they are usually found in the stomach (40% to 60%), small intestine (30%), and colon (15%). GISTs vary con- siderably in their presentation and clinical course, ranging from small benign tumors to massive lesions with necrosis, hemorrhage, and wide metastases', 'role': 'assistant'}]