This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Contraception, Subject name: Gynaecology & Obstetrics
[{'content': 'Least failure in sterilization occurs with : \nSelect and explain. \nA. Falope ring, B. Bipolar cautery, C. Unipolar cauterisation, D. Hulka clip', 'role': 'user'}, {'content': 'Answer: C \nExplanation: The success rates are best when clips and rings are used and worst with electrocoagulation. TEXTBOOK OF GYNECOLOGY SHEILA BALAKRISHNAN SECOND EDITION PAGE NO 393', 'role': 'assistant'}]