This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Nucleotides, Subject name: Biochemistry
[{'content': 'Most abundant free nucleotide in a mammalian cell ? \nSelect and explain. \nA. ATP, B. dATP, C. GTP, D. AMP', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Most abundant free nucleotide in a mammalian cell is ATP', 'role': 'assistant'}]