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
Regarding Bispectral index monitor all are true except 
Select and explain. 
A. Monitors depth of anaesthesia, B. Decrease the dose of agent once BIS value falls below 40, C. Increase the dose of agent once BIS value falls below 40, D. Increase the dose of agent once BIS value goes beyond 60
C: Increase the dose of agent once BIS value falls below 40
Answer: C: Increase the dose of agent once BIS value falls below 40 
Explanation: Increasing BIS value suggests regaining consciousness, so need to increase the dose and vice versa (Target BIS value = 40–60).