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: Surgery
[{'content': 'Which of the following is not a self-retaining urinary catheter: March 2011 \nSelect and explain. \nA. Foley, B. Malecot, C. Gibbon, D. Red rubber', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Ans. D: Red rubber', 'role': 'assistant'}]