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': 'Transition mutation of GATCCT is: \nSelect and explain. \nA. GGTCCT, B. GTTCCT, C. GABCCT, D. GrUGGT', 'role': 'user'}, {'content': 'Answer: A \nExplanation: A i.e. G G T C C T', 'role': 'assistant'}]