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: Biochemistry
[{'content': 'Apart from occurring in nucleic acids, pyrimidines are also found in \nSelect and explain. \nA. Theophylline, B. Theobromine, C. Flavin mononucleotide, D. Thiamine', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Usually, purine and pyrimidine are found in nucleic acids (DNA and RNA) as a part of nucleotides.\nPyrimidines also occur in thiamine (vitamin B1) and alloxan.\nPurine is also a structural component of a number of essential coenzymes, e.g. coenzyme-A, NAD+, NADP+ and FAD+.', 'role': 'assistant'}]