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': 'Beta alanine is formed from \nSelect and explain. \nA. Adenosine and thymine, B. Cytosine and Uracil, C. Cytosine alone, D. Adenosine alone', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Beta alanine is formed from cytosine and Uracil.', 'role': 'assistant'}]