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
For high pressure storage of compressed gases cylinders are made up of – 
Select and explain. 
A. Molybdenum steel, B. Iron + Mo, C. Steel + Cu, D. Cast iron
A: Molybdenum steel
Answer: A: Molybdenum steel 
Explanation: Gas cylinders are made from a steel alloy of molybdenum, which is resistant to corrosion.
Aluminum cylinders are also available in western countries.