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': 'Most common side effect of 5–fluorouracil is : \nSelect and explain. \nA. G.I. toxicity, B. Bone marrow depression, C. Cardiotoxicity, D. Neurotoxicity', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]