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': 'All of the following agents are are tocolytics, EXCEPT: \nSelect and explain. \nA. Ritodrine, B. Salbutamol, C. Isoxsuprine, D. Misoprostol', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Among the above given options, Misoprostol is not a tocolytic. It is a methyl ester of PGE1 which has been used for cervical ripening and induction of labour. Ref: Who Model Formulary 2008 By Mark C. Stua, Maria Kouimtzi, World Health Organization, Suzanne R. Hill, Pages 450-51; Dutta textbook of Obstetrics 6th edition, Pages 175, 505 and 507-508', 'role': 'assistant'}]