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: Anaesthesia
Semiclosed circuit system 
Select and explain. 
A. Needs advanced monitoring, B. Complex, C. More environmental pollution, D. More economical
C: More environmental pollution
Answer: C: More environmental pollution 
Explanation: Semiclose breathing circuit is less economical, causes more environmental pollution. It is simple portable and no need of advanced monitoring.