Consider the Following Work Breakdown Structure In Crashing This Project, Which Activity Should Be the First

Consider the following work breakdown structure: $$\begin{array} { l c c c c } \text { Activity } & \text { Precedes } & \begin{array} { c } \text { Normal } \\\text { Time (wks) }\end{array} & \begin{array} { c } \text { Crashing } \\\text { Cost } \left( 1 ^ { \text {st } } \text { week } \right)\end{array} & \left( 2 ^ { \text {nd } } \right. \text { week) } \\\hline \text { Start } & \text { A, B } & - & - & - \\\text { A } & \text { C, D } & 6 & 8 & - \\\text { B } & \text { G } & 4 & 5 & 6 \\\text { C } & \text { E } & 4 & - & - \\\text { D } & \text { F } & 5 & 6 & 6 \\\text { E } & \text { H } & 6 & 8 & 8 \\\text { F } & \text { H } & 6 & 7 & 10 \\\text { G } & \text { I } & 8 & 3 & 5 \\\text { H } & \text { End } & 5 & 12 & 15 \\\text { I } & \text { End } & 6 & 5 & -\end{array}$$ In crashing this project, which activity should be the first to be reduced?