The correct option is A AUG
Codons are the nucleotide base triplets that specify a particular amino
acid in proteins. The start codon specifies the first
codon of mRNA transcript that is translated. It codes for
methionine in eukaryotes and a modified Met in prokaryotes. "AUG" is the
most common start codon. AUG and UGA are start and stop codons
respectiveiy. Thus, the correct answer is option A.