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: Skin
The most impoant constituent in soda lime for reabsorption of CO2 in a closed circuit is: 
Select and explain. 
A. Sodium hydroxide, B. Barium hydroxide, C. Calcium hydroxide, D. Potassium hydroxide
C: Calcium hydroxide
Answer: C: Calcium hydroxide 
Explanation: Ans. c. Calcium hydroxide