This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Gynaecology & Obstetrics
[{'content': 'In which case homologus aificial insemination is used in females : \nSelect and explain. \nA. Hormonal disturbances, B. Tubal block, C. Cervical factor, D. All of the above', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Cervical factor', 'role': 'assistant'}]