sort the list a$[]=\{20,13,4,34,5,15,90,100\}$

a$)$heap sort $($insert the elements of the array into a minheap and delete them from the Minheap into the same array$).$ Just show the steps and no need to write any algorithms

b$)$ what is the worst$-$case scenario of Merge$-$sort? explain.

c$)$ explain the average case of Insertion sort.