This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Biochemistry
Chain initiation in protein synthesis is by 
Select and explain. 
A. AUG, B. GLA, C. UGA, D. UAG
A: AUG
Answer: A: AUG 
Explanation: Initiation codon AUG codes for methionine.