This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Physiology
Methoctramine is a 
Select and explain. 
A. Selective M1 antagonist, B. Selective M2 antagonist, C. Selective M3 antagonist, D. Nonselective (M1+M2 ) agonist
B: Selective M2 antagonist
Answer: B: Selective M2 antagonist 
Explanation: .