I need help with part D please

Development of Version 2.0 of a particular accounting software product is being considered by Jose Noguera's technology firm in Baton Rouge. The activities necessary for the completion of this project are listed in the following table: Normal Time (weeks) 4 2 3 Activity B D E F G Crash Time (weeks) 3 1 3 4 3 2 2 Normal Cost $2,200 $2,300 $600 $2,500 $900 $3,400 $1,400 Total Cost with Immediate Crashing Predecessor(s) $2,900 $3,000 $600 $2,800 A $1,275 B $4,900 $2,000 DE mo B 6 3 4 a) Based on the given information regarding the activities for the project, the project length - 16 weeks b) The total cost required for completing this project on normal time - $ 13,300) c) For reducing the duration of the project by one week, the activity that should be crashed first is activity D The cost of the project based on the first activity nolected for crashing will increase by $ 75) d) The maximum weeks by which the project can be reduced by crashing = Total cost of crashing the project to minimum (or maximum weeks possible) = $ weeks