Option B) CAU
Explanation:
The codon is a combination of three nucleotides of either adenine, cytosine, guanine or uracil that joins together to form a triplet code and carried by the messenger RNA (mRNA) molecule.
One of such is CAU (with cytosine, Adenine and uracil nucleotides) present on mRNA molecule and codes for the amino acid named Histidine.
Thus, the codon, CAU will always be translated to add histidine to the polypeptide chain