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: Gynaecology & Obstetrics
Zygote with zona pellucida reaches uterine cavity by : 
Select and explain. 
A. 2 days, B. 4 days, C. 5 days, D. 6 days
B: 4 days
Answer: B: 4 days 
Explanation: 4 days