Answer:
tRNA and mRNA
Step-by-step explanation:
The process being described here is translation, which is how proteins are synthesised in the cell. In order to translate an mRNA sequence (made during the transcription of DNA to mRNA), the protein synthesis machinery requires codon-anticodon pairing.
tRNAs are specialised RNAs that recognise specific sequences on mRNA, and deliver the appropriate amino acid to the protein synthesis machinery.
The tRNA recognises a triplet code on the mRNA (3 nucleotides in a row, also called a codon). This is because it possesses the complementary anticodon. It can binds to the codon, and can then deliver the required amino acid to the machinery to build a growing polypeptide chain.
See the attachment for a good visualisation of this process