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
Colour of Entonox cylinder is 
Select and explain. 
A. Black body, white shoulder, B. Grey body, black and white shoulder, C. Black body, brown and white shoulder, D. Blue body, white shoulder
D: Blue body, white shoulder
Answer: D: Blue body, white shoulder 
Explanation: Entonox cylinder has blue body and white shoulder.