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: Pharmacology
Which of the following drug is preferred in acute attack of asthma during labour 
Select and explain. 
A. Salbutamol, B. Formeterol, C. Ipratropium, D. Zafirleukast
C: Ipratropium
Answer: C: Ipratropium 
Explanation: Ipratropium is a M3-antagonist used in acute attack of asthma during labour, as Beta 2-agonists are avoided because of tocolytic action.