This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Introduction and gametogenesis., Subject name: Anatomy
[{'content': 'When does a secondary oocyte complete its second meiotic division to become a mature ovum? \nSelect and explain. \nA. At ovulation, B. Before ovulation, C. At feilization, D. At pubey', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Secondary oocyte complete its second meiotic division to become a mature ovum at feilization. At ovulation, a secondary oocyte begins meiosis II, but this division is arrested at metaphase. The secondary oocyte will remain arrested in metaphase until a sperm penetrates it at feilization. Therefore, the term "mature ovum\'" is somewhat of a misnomer because it is a secondary oocyte that is feilized, and, once feilized, the new diploid cell is known as a zygote. If feilization does not occur, the secondary oocyte degenerates.', 'role': 'assistant'}]