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
Which model of DNA was discovered by Watson and Crick 
Select and explain. 
A. A- DNA, B. B- DNA, C. C-DNA, D. Z- DNA
B: B- DNA
Answer: B: B- DNA 
Explanation: Most common form.Right handed double helix.Highly flexible.Watson and Crick model describes the B- form of DNA.