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
Mechanism of action of Progesterone only pill is: 
Select and explain. 
A. Makes mucus viscid, B. Prevents ovulation, C. Antispermatozoic, D. None of the above
A: Makes mucus viscid
Answer: A: Makes mucus viscid 
Explanation: Makes mucus viscidq