This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Molecular Genetics, Subject name: Biochemistry
The Pentose sugar in nucleic acid is: 
Select and explain. 
A. Ribulose, B. Ribose, C. Xylulose, D. Xylase
B: Ribose
Answer: B: Ribose 
Explanation: (Ribose): Ref (204-R.S.7th)Pentoses* D. Ribose is a constituents of nucleic acid RNA: also as constituents of certain coenzyme eg. FAD, NAD, coenzyme A* D-2 deoxyribose is constituent of DNA* Phosphate esters of ketopentoses - D-ribulose and D-xylulose occurs as intermediates in HMP-shunt* L-xylulose is a metabolite of D-glucuronic acid and is excreted in urine of humans affected with a hereditary abnormality in metabolism called Pentosuria* L-fucosa (methyl pentose) occurs in glycoproteins* D-lyxose: forms a constituent of lyxoflavin isolated from human heart muscle whose function is not clear.