# The cell reaction of an electrochemical cell is $Cu^{+2}(C_1) + Zn \rightarrow Zn^{+2}(C_2) + Cu$. The change in free energy will be the function of :
( A ) ln$(C_1 + C_2)$
( B ) ln $C_1$
( C ) ln $\frac{C_2} {C_1}$
( D ) ln $C_2$