This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Pituitary-Hypothalmic System and Thyroid, Subject name: Pharmacology
Which of the following is not a GnRH agonist? 
Select and explain. 
A. Leuprolide, B. Nafarelin, C. Ganirelix, D. Busurelin
C: Ganirelix
Answer: C: Ganirelix 
Explanation: GnRH Agonist Drugs Leuprolide Nafarelin Goserelin Buserelin -They are all injectables. -They all have flare up reaction as adverse effect when given in continuous form GnRH Antagonist Drugs Cetrorelix Ganirelix Abarelix Degarelix -Given as injectables -They do not increase the sex hormone