This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Genito Urinary System, Subject name: Radiology
[{'content': 'Difference of - cm or more in the size of two kidneys raises a possibility of unilateral disease? \nSelect and explain. \nA. 1, B. 1.5, C. 2, D. 2.5', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Ans CDifference in sizes between the two kidneys up to 1.5 - 2 cm is not significant with left always being slightly larger than right', 'role': 'assistant'}]