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: Pharmacology
[{'content': 'Mechanism of action of vincristine in the treatment of ALL is : \nSelect and explain. \nA. Inhibition of topoisomerase II to cause breaks in DNA strands, B. Alkylation and cross linking DNA strands, C. Inhibition of DNA mediated RNA synthesis, D. Inhibition of polymerization of tubulin to form microtubules', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]