Stadium Construction Project Problem: What is the project duration?

$\backslash$table$[[$ACTIVITY$,$IMMEDIATE PREDECESSOR,DURATION $($days$)],[$A$,-,1],[$B$,$A$,4],[$C$,$A$,3],[$D$,$A$,7],[$E$,$B$,6],[$F$,$C$,$D$,2],[$G$,$E$,$F$,7],[$H$,$D$,9],[$I$,$G$,$H$,4]]$

$21$ days

$20$ days

$23$ days

$22$ days

$24$ days