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: Anatomy
[{'content': 'Boundary of triangle of auscultation is not formed by? \nSelect and explain. \nA. Senatus anterior, B. Scapula, C. Trapezius, D. Latissimus dorsi', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Serratus anterior.', 'role': 'assistant'}]