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: Medicine
In an ICU patient is on invasive monitoring, All are causes of bacterial sepsis except - 
Select and explain. 
A. Orotracheal intubation, B. Intra arterial line, C. Humidified air, D. Central venous catheter
C: Humidified air
Answer: C: Humidified air 
Explanation: None