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
Characteristic of an ideal gas is – 
Select and explain. 
A. Volume is directly proportional to change in pressure, B. Volume is inversely proportional to change in temperature, C. At absolute temp. volume of gas is 1, D. Obeys Charles, Byles and Avagadro laws
D: Obeys Charles, Byles and Avagadro laws
Answer: D: Obeys Charles, Byles and Avagadro laws 
Explanation: An ideal gas is one which obeys Boyle's law, charle's law and Avogadro law :-
The ideal gas equation is :-

Volume (v) = (number of moles (n) × gas constant (R) × Temperature (T)) / Pressure P  

Byole's law :-At a constant temperature, volume of gas is inversely proportional to pressure (see ideal gas equation).
Charle's law :- At a constant pressure, volume of gas is direct proportional to temperature (see ideal gas equation).
Avogardo's low :- Equal volumes of gas at same temperature & pressure contains same number of moleules.
At standard temperature the volume of a mole of gas is 22.4 liters.