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
Commonest side effect of antihistaminics is? 
Select and explain. 
A. Sedation, B. Tinnitus, C. Euphoria, D. Lassitude
A: Sedation
Answer: A: Sedation 
Explanation: Ans. is 'a' i.e., Sedation o Sedation, diminished aleness, concentration, light headedness, motor in coordination, fatigue and tendency to fall asleep are the most common side effects.