This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Haematology, Subject name: Anatomy
[{'content': 'Examination of a peripheral smear demonstrates leukemia composed of small mature lymphocytes without blast forms.which of the following is most likely age of this patient? \nSelect and explain. \nA. 1year, B. 20 years, C. 45years, D. 65years', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Different leukemias tend to affect populations of different ages. The disease described is chronic lymphocytic leukemia which is a disease of older adults.(ref Robbins 8th/604, 9/e p593)', 'role': 'assistant'}]