What is the earliest start $($ES$)$ time for activity D$?$

$\backslash$table$[[$Activity ID$,$Predecessor,Duration $($in days$)],[$A$,$None,$9],[$B$,$A$,2],[$C$,$A$,3],[$D$,$B$,$ C$,7],[$E$,$D$,6],[$F$,$E$,1],[$G$,$D$,4],[$H$,$G$,$ F$,5]]$

$23$

$12$

$14$

$18$