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: Radiology
[{'content': "Most common cause of 'target lesion' in stomach is: \nSelect and explain. \nA. Melanoma, B. Carcinoid, C. Lymphoma, D. Fibroma", 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. Melanoma', 'role': 'assistant'}]