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
All except one belongs to intermediate pressure system of anaesthetic machine 
Select and explain. 
A. Emergency oxygen flush, B. Yoke assembly system, C. Pipeline pressure gauge, D. Pipeline supply
B: Yoke assembly system
Answer: B: Yoke assembly system 
Explanation: Yoke assembly system belongs to high pressure system of anaesthetic machine.