This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Fertilization and Development of Embryo, Subject name: Anatomy
[{'content': 'Spermatogonium to Spermatozoon: \nSelect and explain. \nA. 64 days, B. 74 days, C. 84 days, D. 94 days', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ans. (b) 74 daysRef: I.B. Singh 9th ed. /14-15', 'role': 'assistant'}]