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
Diphenhydramine used as antitussive is a 
Select and explain. 
A. Central opioid agonist, B. NMDA blocker, C. Antihistamine, D. Mucolytic
C: Antihistamine
Answer: C: Antihistamine 
Explanation: Diphenhydramine is an anti histamine used for mild cough.