$\backslash$table$[[$Activity Normal$\_$timeCrash$\_$timeNormal$\_$costCrash$\_$costSlack$],[$A$,31,21,4300,7100,0],[$B$,13,13,5200,5200,2],[$C$,35,31,4700,6900,0],[$D$,31,31,5300,5300,2],[$E$,12,12,5400,5400,1],[$F$,23,23,4300,4300,1]]$

The table shows normal time $($in days$),$ crash time $($in days$),$ normal cost $($in dollars$),$ crash cost $($in dollars$)$ and slack time $($in days$)$ of activities in a small construction project. According to this table which activity must be crashed first? Assume there is only one critical path. $($Only type the name of the activity, Example: A$.$ @orsdemir. Copyrighted content. Cannot be posted.$)$