c
we know that from ideal gas equation, $PV = nRT$ now, $n=$ number of moles of gas $=\frac{N}{N_{A}}$, where $N=$ number of molecules of the gas and $N _{ A }$ is the Avogadro's number
So, putting the value of $n$ in ideal gas equation, we get $PV =\frac{ N }{ N _{ A }} RT$
this means that pressure of the gas is proportional to the number of molecules of the gas at constant temperature and volume
So, if we double the number of molecules of the gas $(2 x )$, then pressure will also double