$1\mathrm{.}2$ Activity Selection $[17$ points$]$ Consider the activility selection problem discussed in the lecture slides with the following instance: $[0,6),[5,7),[3,8),[1,4),[3,5),[2,13),[5,9),[6,10),[8,12),[8,11),$ where each job is represented by an interval indicating their starting and finishing times. Based on the given instance, answer the following questions. $($i$)(3$ points$)$ Is the optimal solution unique? If yes, give the unique optimal solution; If no$,$ give as many optimal solutions as possible. $($ii$)(2$ points$)$ Show the greedy solution based on Earliest$-$Finish$-$Time$-$First $($EFTF$),$ and argue if it is unique.