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
Most common side effect of 5–fluorouracil is : 
Select and explain. 
A. G.I. toxicity, B. Bone marrow depression, C. Cardiotoxicity, D. Neurotoxicity
A: G.I. toxicity
Answer: A: G.I. toxicity 
Explanation: None