This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General anaesthesia, Subject name: Anaesthesia
What is the critical temperature of N2O 
Select and explain. 
A. 118 degrees, B. -88 degrees, C. 26 degrees, D. 36.5 degrees
D: 36.5 degrees
Answer: D: 36.5 degrees 
Explanation: In thermodynamics, a critical point (or critical state) is the endpoint of a phase equilibrium curve. The most prominent example is the liquid-vapor critical point, the endpoint of the pressure-temperature curve that designates conditions under which a liquid and its vapor can coexist. At higher temperatures, the gas cannot be liquefied by pressure alone. At the critical point, defined by a critical temperature Tc and a critical pressure pc, phase boundaries vanish. critical temperature of N2O: 38.5degC