The following table details the tasks required for Indiana$-$based Frank Pianki Industries to manufacture a fully portable industrial vacuum cleaner. The times in the table are in minutes. Demand forecasts indicate a need to operate with a cycle time of $11$ minutes.

$\backslash$table$[[$Activity Activity Description,$\backslash$table$[[$Performance$],[$Time $($mins$)]],$Predecessors,$],[$A $,$ Attach wheels to tub,$4\mathrm{.}0,-,],[$B Attach motor to lid,$1\mathrm{.}5,-,],[$C Atta$$n battery pack,$2\mathrm{.}8,$B$,],[$D Attach safety cutoff,$4\mathrm{.}0,$C$,],[$E $,$ Attach filters,$3\mathrm{.}0,$B$,],[$F $,$ Attach lid to tub,$2\mathrm{.}0,$A$,$ E$,],[$G Assemble,$3\mathrm{.}2,,],[,$attachments,,$-],[$H Function test,$4\mathrm{.}0,$D$,$ F$,$ G$,],[$I $,$ Final inspection,$2\mathrm{.}0,$H$,],[$J Packing,$2\mathrm{.}0,$I,$]]$

a$-$b$)$ One of the possible assignment of tasks to workstations is shown correctly in Fig. $2.$

The efficiency of the assembly line with $3$ workstations $=95\%($enter your response rounded to two decimal places$).$

c$)$ The goal is to have $100\%$ efficiency. Is this possible? No

d$)$ The theoretical minimum number of workstations $=$ whole number$).$

$($round your response up to the next