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
Which of the following drug is not the first line treatment for anovulatory abnormal uterine bleeding in a 13-year-old girl? 
Select and explain. 
A. Tranexemic acid, B. Mefenamic acid, C. Progesterone, D. Estrogen + progesterone
B: Mefenamic acid
Answer: B: Mefenamic acid 
Explanation: Ans. b. Mefenamic acid