According to the first law of thermodynamics, `DeltaU=q+w`. In special cases the statement can be expressed in different ways. Which of the following is not a correct expression ?
A. At constant temperature, `q=-w`
B. When no work is done , `DeltaU=q`
C. In gaseous system , `DeltaU=q+PDeltaV`
D. When work is done by the system : `DeltaU=q+w`
