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
DNA denaturation is measured by absorbance at 
Select and explain. 
A. 220nm, B. 230nm, C. 240 nm, D. 260nm
D: 260nm
Answer: D: 260nm 
Explanation: Increase in the optical absorbance of UV light by Purine and Pyrimidine bases called hyperchromicity.( DNA bases absorbs UV light of 260nm).