Which of the following nucleotide triplets best represents a codon?A) a triplet separated spatially from other tripletsB) a triplet that has no corresponding amino acidC) a triplet at the opposite end of tRNA from the attachment site of the amino acid D) a triplet in the same reading frame as an upstream AUGE) a sequence in tRNA at the 3' end

A codon is a sequence of three nucleotides on a messenger ribonucleic acid (mRNA) specifying one of the 22 proteinigenic amino acids whose succession on the messenger RNA determines the primary structure of the protein to be synthesized. As the messenger RNAs consist of a succession of several tens to several hundreds of nucleotides, it is also several tens to several hundreds of amino acids that can thus be assembled linearly to form protein chains.