This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Endocrinology and breast, Subject name: Anatomy
[{'content': 'Best diagnostic method for breast lump is \nSelect and explain. \nA. USG, B. Mammogram, C. Biopsy, D. FNAC', 'role': 'user'}, {'content': 'Answer: C \nExplanation: First investigation for tissue sampling : FNAC Best and diagnostic investigation : Biopsy Ref: Sabiston 20th edition Pgno: 826-828', 'role': 'assistant'}]