This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Multiple Pregnancy, Subject name: Gynaecology & Obstetrics
[{'content': 'Monochorionic monoamniotic twins occur when splitting of zygote occurs: \nSelect and explain. \nA. At bilaminar germ disc stage, B. At 8 cell stage, C. At 2 cell stage, D. At early blastocyst stage', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Ans. is d, i.e. At early blastocyst stageMonochorionic: Monoamniotic twins are seen when division occurs at more than 8 days which means Blastocyst is formed we all know Implantation occurs in stage of blastocyst and implantation begins by 6 to 7 days after fertilization and is completed by 10th day after fertilization. Hence between this time the stage is Blastocyst.', 'role': 'assistant'}]