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
An RNA molecule is extracted from culture of gram negative bacteria. This extract contained dihydrouracil, Pseudouridine thymidine residues. which of the following is most likely composition of 3' end of this molecule 
Select and explain. 
A. AUG, B. CCA, C. UAG, D. PolyA
B: CCA
Answer: B: CCA 
Explanation: The given RNA is tRNA as it has unusal bases. It has CCA sequence at its 3' end that is used as recognition sequence by proteins.