$1.[10$pts$]$ Which operation is the main bottleneck process for the line? Is variability increased or decreased downstream from it$?$ Explain the rationale for your answer.

$2.[15$pts$]$ Calculate CVe, re$,$ and CVd for OP$1.$ You may use the spreadsheet to confirm, but must show work.

$3.[15$pts$]$ It is desired to reduce flowtime and WIP for the system significantly. There are four alternatives, each of approximately equal cost:

a$.$OP$4$ and OP$2$ positions can be swapped on the line

b$.$The processing time standard deviation of OP $2$ can be reduced by $(1)/(2).$

c$.$OP$2$ processing time can be reduced to $1\mathrm{.}65$

d$.$The MTTF of OP$2$ can be extended to $200$ hours.

Which option should be selected? Justify your answer. Use the spreadsheet.