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': 'Nucleoside is made up of \nSelect and explain. \nA. Pyrimidine, B. Histone, C. Sugar, D. Purine', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Nucleosides are glycosylamines that can be thought of as nucleotides without a phosphate group. A nucleoside consists simply of a nucleobase (also termed a nitrogenous base) and a 5-carbon sugar (either ribose or deoxyribose)', 'role': 'assistant'}]