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
Dextromethorphan is an : 
Select and explain. 
A. Antihistaminic, B. Antitussive, C. Expectorant, D. Antiallergic
B: Antitussive
Answer: B: Antitussive 
Explanation: None