Which of the Following Expressions Does Not Represent a Proper $\frac { - \Delta [ \mathrm { A } ] } { \Delta \mathrm { t } }$

Which of the following expressions does not represent a proper expression for the rate of this reaction?
2A + 3B ? F + 2G

A) $\frac { - \Delta [ \mathrm { A } ] } { \Delta \mathrm { t } }$
B) $\frac { - \Delta [ \mathrm { B } ] } { 3 \Delta \mathrm { t } }$
C) $\frac { \Delta [ F ] } { \Delta t }$
D) $\frac { \Delta [ \mathrm { G } ] } { 2 \Delta \mathrm { t } }$
E) $\frac { - \Delta [ \mathrm { A } ] } { 2 \Delta \mathrm { t } }$