The dependence of Gibbs free energy on pressure for an isothermal process of an ideal gas is given by
A. `DeltaG_(T)=nRTln.(P_(2))/(P_(1))`
B. `DeltaG_(T)=nRTln.(V_(2))/(V_(1))`
C. `DeltaG_(T)=nRTlog.(P_(1))/(P_(2))`
D. `DeltaG_(T)=nRTlog.(V_(2))/(V_(1))`