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
Not true about microtubules is 
Select and explain. 
A. Dynamic instability, B. Polarity, C. Charged, D. GTP not required
D: GTP not required
Answer: D: GTP not required 
Explanation: For the assembly of microtubules, GTP is required.