The Diagram Below Shows the Activities on the Nodes, and the Table

The diagram below shows the activities on the nodes, and the table shows the normal time and crash time (in days) and cost for each activity.

$$\begin{array} { | c | c | c | c | } \hline \text { Activity } & \text { Normal Time } & \text { Crash Time } & \begin{array} { c } \text { Cost per day } \\\text { to crash }\end{array} \\\hline \text { A } & 6 & 6 & - - - \\\hline \text { B } & 10 & 8 & \$ 100 \\\hline \text { C } & 5 & 4 & \$ 300 \\\hline \text { D } & 4 & 1 & \$ 700 \\\hline \text { E } & 9 & 7 & \$ 500 \\\hline \text { F } & 2 & 1 & \$ 650 \\\hline\end{array}$$
-Which activity should be crashed to reduce the project completion time by one day?

A) B
B) C
C) D
D) E