The correct answer is:
B) 0 J
Let's see why. The work done by the gas is equal to
[tex]W=p \Delta V[/tex]
where
p is the pressure
[tex]\Delta V[/tex] is the variation of volume of the gas.
However, the problem says that the volume is kept constant (2.0 L), so the variation of volume is zero: [tex]\Delta V=0[/tex], and the work done is zero as well.