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
All are the processing reaction in tRNA, except: 
Select and explain. 
A. CCA tailing, B. Methylation of bases, C. Poly A tailing, D. Trimming of 5’ end
C: Poly A tailing
Answer: C: Poly A tailing 
Explanation: Post-transcriptional modification of tRNA precursor:

Standard bases (A, U, G, C) undergo methylation, reduction, deamination, rearranged glycosidic bond.
Cleavage and attachment of CCA terminal at 3’ end takes place in cytoplasm.
Methylation of tRNA takes place in nucleus.

Note:- Poly A tailing is a processing step of mRNA primary transcript.
Reference- Harper 30th edition