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': 'Concentration of DNA is measured by: \nSelect and explain. \nA. Absorption at 260 nm, B. D-oxyribose estimation, C. Infrared examination, D. Ultrasound examination', 'role': 'user'}, {'content': 'Answer: A \nExplanation: A i.e. Absorption at 260 nmConcentration (and quality) of nucleotides and ncleic acid (DNA/RNA) is measured in terms of "absorbance at 260 nmQ" with a Ultraviolet (UV) spectrophotometer.', 'role': 'assistant'}]