Determine the critical path for the project using slack.

\begin{tabular}{|l|l|l|l|l|} \hline Activity & Immediate Predecessor & Optimistic Time & Most Likely Time & Pessimistic Time \\ \hline A & & 4 & 6 & 8 \\ \hline B & --- & 2 & 4 & 6 \\ \hline C & - & 1 & 2 & 3 \\ \hline D & B & 6 & 7 & 8 \\ \hline E & A & 2 & 4 & 6 \\ \hline F & E & 6 & 10 & 14 \\ \hline G & D & 1 & 3 & 5 \\ \hline H & C, D & 3 & 6 & 9 \\ \hline I & F, G, H & 5 & 11 & 17 \\ \hline \end{tabular}