$6.[30$ points$]$ Consider following project. Activity Activity Time $($weeks$)$ Immediate Predecessor Number of workers reqd. A $42$ B $31$ C $33$ D B$,$ C $42$ E A $41$ F D $33$ a$.$ Draw a project network. If you draw on a paper, scan it and insert it to the document with answers, Images submitted separately will not be graded. b$.$ Develop resource requirement plan $($similar to figure $6\mathrm{.}5,6\mathrm{.}7).$ See presentation slide $10$ for an example. c$.$ Assume that each task can be performed independently of the other tasks. $($No predecessor relationships$).$ Now, do a resource leveling. How many workers are required? What is the project completion time? Show all work to earn credit. d$.$ Assume that each task can be performed independently of the other tasks. But now, you have only $3$ workers available at any given time. Perform resource$-$limited scheduling. What is the new completion time for the project? Show all work to earn credit.