This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Anaesthetic equipments, Subject name: Anaesthesia
The most impoant constituent in soda lime for reabsorption of CO2 in a closed circuit 
Select and explain. 
A. Sodium hydroxide, B. Barium hydroxide, C. Calcium hydroxide, D. Potassium hydroxide
C: Calcium hydroxide
Answer: C: Calcium hydroxide 
Explanation: Sodalime is most common Co2 absorbant . Indicators added to sodalime changes the color of sodalime . It contains 94% Ca(OH)2 , 5%NaOH,1% KOH.