This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Mutations & Codons, Subject name: Biochemistry
All of the following are synonymous codon pair EXCEPT 
Select and explain. 
A. CAU & CAC, B. AUU & AUC, C. AUG & AUA, D. AAU & AAC
C: AUG & AUA
Answer: C: AUG & AUA 
Explanation: Synonymous codons Codons that specify the same amino acids. E.g- GGA, GGG, GGU, and GGC codes for glycine Methionine is coded by AUG only. So, there is no synonymous codon for methionine.