This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General anatomy, Subject name: Anatomy
[{'content': 'At 30 days of intrauterine life \nSelect and explain. \nA. Hea stas beating, B. Cerebellum develops, C. Optical vesicle appears, D. Pinna appears', 'role': 'user'}, {'content': "Answer: C \nExplanation: *Optical vesicle come in contact with surface ectoderm and lens place is forming by the 4th week of IUL - the eyes begin to develop as a pair of diveicula from the lateral aspects of the forebrain. These diveicula make their appearance before the closure of the anterior end of the neural tube; after the closure of the tube, they are known as the optic vesicles. *Ear pinna or auricle stas forming by the 5th week of IUL *Cerebellum stas forming by the 8th week of IUL *The baby's heabeat stas as the blood flow begins by 22nd day of IUL (Reference: I B Singh's Embryology, 10th edition, pg 374, 281)", 'role': 'assistant'}]