This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General obstetrics, Subject name: Anatomy
Zona hatching occurs: 
Select and explain. 
A. 4 days after feilisation, B. 5 days after feilisation, C. 6 days after feilisation, D. 8 days after feilisation
B: 5 days after feilisation
Answer: B: 5 days after feilisation 
Explanation: Zona hatching occurs just before the implantation i.e,5 days after feilisation. Ref: Datta textbook of Obstetrics - 9e pg24.