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: Gynaecology & Obstetrics
The blebs of vaginitis emphasematosa contains: 
Select and explain. 
A. H2S, B. H2, C. NO2, D. CO2
D: CO2
Answer: D: CO2 
Explanation: CO2