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': 'Mechanism of action of Progesterone only pill is: \nSelect and explain. \nA. Makes mucus viscid, B. Prevents ovulation, C. Antispermatozoic, D. None of the above', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Makes mucus viscidq', 'role': 'assistant'}]