This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Metabolism of nucleic acids, Subject name: Biochemistry
[{'content': 'Which of the following base is not found in nucleic acids? \nSelect and explain. \nA. Adenine, B. Guanidine, C. Uracil, D. Cytosine', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Adenine, Guanine, Cytosine, Thymine, and Uracil are Nucleic acids Ref-Harpers illustrated biochemistry 30/e p380', 'role': 'assistant'}]