All are the processing reaction in tRNA, except:: (A) CCA tailing, (B) Methylation of bases, (C) Poly A tailing, (D) Trimming of 5’ end
Answer is C. 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