This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Maternal Anatomy and Physiology, Subject name: Gynaecology & Obstetrics
After how many days of ovulation, embryo implantation occurs? 
Select and explain. 
A. 3-5 days, B. 6-9 days, C. 10-12 days, D. 13-15 days
B: 6-9 days
Answer: B: 6-9 days 
Explanation: After the feilization process, embryo is formed in the ampulla and it reaches the uterine cavity on 3rd - 4th day and the implantation occur between 6th to 9th day of ovulation