This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Molecular Biology, Subject name: Biochemistry
In which phase of cell cycle, proof reading occurs? 
Select and explain. 
A. G1, B. S, C. G2, D. M
B: S
Answer: B: S 
Explanation: EVENTS PHASE of cell cycle Proofreading S phase Most repairs G1 phase Mismatch repair G2 phase