A house flipper found a diamond in the rough and, after buying it at a sheriff's auction, has identified six systems that need significant work. The estimated completion times $($in weeks$)$ and costs are identified in the table alongside a set of expedited completion times and the crash costs.

$\backslash$table$[[$Activity$,$Normal time,Crash time,Normal Cost,Crash Cost,Predeces$],[$A$,10,7,5,000,7,200,],[$B$,15,10,10,000,15,000,$A$],[$C$,20,15,18,000,24,000,$B$],[$D$,20,17,20,000,26,000,],[$E$,15,12,12,000,14,700,$D$],[$F$,12,7,7,200,12,700,$E$]]$

What is the shortest time to complete this project?

$$ a$.33$ weeks

b$.34$ weeks

c$.35$ weeks

d$.36$ weeks