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: Physiology
[{'content': 'Not true about microtubules is/are: \nSelect and explain. \nA. Dynamic instability, B. Polarity, C. Charged, D. GTP not required', 'role': 'user'}, {'content': 'Answer: D \nExplanation: D i.e. GTP not required', 'role': 'assistant'}]