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
All of the following are actions of muscarinic antagonists except: 
Select and explain. 
A. Decreases gastric secretion, B. Prolongs A–V conduction, C. Decreases tracheobronchial secretions, D. Causes contraction of sphincter pupillae
B: Prolongs A–V conduction
Answer: B: Prolongs A–V conduction 
Explanation: None