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
Patients taking a β–adrenergic receptor blocking drug may experience all of the following except: 
Select and explain. 
A. Exacerbation of existing heart block, B. Precipitation of heart failure, C. Nasal blockage, D. Cold extremities
C: Nasal blockage
Answer: C: Nasal blockage 
Explanation: None