Draw the different paths from the table and select the critical path

\begin{tabular}{|c|c|c|} \hline Activity & Immediatepredecessoractivity & Durationofactivities(Days) \\ \hline a & - & 20 \\ \hline b & a & 10 \\ \hline c & b & 8 \\ \hline d & a & 11 \\ \hline e & c,d & 7 \\ \hline f & e & 6 \\ \hline g & d & 12 \\ \hline h & e & 13 \\ \hline i & g,h & 5 \\ \hline \end{tabular}