This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Fundamental concepts, Subject name: Anaesthesia
All statements are true about gas cylinders except 
Select and explain. 
A. Pressure of N2O is 745 psig at 20 degrees centigrade, B. Higher pressure indicates impurity in N2O, C. N2O is in liquid form, D. Emergency oxygen 'E' cylinder has more gas than 'H' cylinder
D: Emergency oxygen 'E' cylinder has more gas than 'H' cylinder
Answer: D: Emergency oxygen 'E' cylinder has more gas than 'H' cylinder 
Explanation: .N20 is stored in blue steel cylinders as a colorless liquid under 745 psi pressure and is in equilibrium with the gas phase (approximately 50 atmospheres at room temperature). The tank maintains that pressure until it is empty.