The City Commission of Nashville has decided to build a botanical garden and picnic area in the heart of the city for the recreation of its citizens. The precedence table for all the activities required to construct this area successfully is as follows:

$\backslash$table$[[$Code$,$Description,$\backslash$table$[[$Time$],[($hrs$)]],$Immediate Predecessor$($s$)],[$A$,\backslash$table$[[$Find location; determine resource$],[$requirements$]],15,$None$],[$B$,$Requisition of lumber and sand,$60,$A$],[$C$,$Dig and grade,$105,$A$],[$D$,$Saw lumber into appropriate sizes,$35,$B$],[$E$,$Position lumber in correct locations,$20,D,C$