This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Metabolism of nucleic acids, Subject name: Biochemistry
Abnormal base in tRNA is 
Select and explain. 
A. Dihydrouracil, B. Orotic acid, C. Methyl Xanthine, D. Cystine
A: Dihydrouracil
Answer: A: Dihydrouracil 
Explanation: The D Arm or DHU region is so named due to the presence of a dihydrouridine in that areaThe DHU arm serves as the recognition site for the enzyme which adds the amino acidRef: DM Vasudevan, 7th edition, page no: 597