$($c$)$ For the following activity table, find different possible crash times and corresponding costs for the project:

$\backslash$table$[[$Activity$,$Predecessor,Duration $($day$),$Cost $($USD$)],[$Normal$,$Crash,Normal,Crash$],[$a$,---,4,2,40,80],[$b$,$a$,5,4,30,50],[$c$,$a$,$ b$,3,3,40,40],[$d$,$c$,5,2,60,120],[$e$,$c$,$ d$,4,4,50,50],[$f$,$d$,$ e$,3,1,40,90]]$

Please draw activity on arrow network diagram for a super like $.$