Which of the following is true?
a) The inert (or noble gases) are ideal and obey the ideal gas law
(Pv-nRT) under any conditions.

b) The molecules in a gas of low pressure and high temperatures
have practically no attraction for one another because they are
so far apart.

c) The volume actually occupied by the individual molecules of a
gas under ordinary conditions is very large compared with the
total volume of the gas.

d) The molecules of a gas do not necessarily move in a straight
line but go in random directions and often change directions.