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': 'Mutations are due to changes in: \nSelect and explain. \nA. DNA nucleotide sequence, B. RNA nucleotide sequence, C. Amino acid sequence of ribonuclease, D. Cell walls', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]