This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Development period- week 1,2,3,4, Subject name: Anatomy
[{'content': 'Implantation occurs at:- \nSelect and explain. \nA. 5th day after feilization, B. 7th day after feilization, C. 8th day after feilization, D. 9th day after feilization', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Implantation of blastocyst in uterine cavity occurs on 6-7th day after feilization.', 'role': 'assistant'}]