We assume we have $N$ naturals to sort. Determine the correct running time $($big$-$Oh notation$)$ of each of the following four algorithms: Insertion sort, Heapsort, Mergesort and Quicksort, in the case of a sorted input $($presorted elements$).$

Select one or more:

a$.$ Quicksort runs in $O(NlogN)$ if the pivot is chosen at random

b$.$ Mergesort runs in $O(NlogN)$

c$.$ Insertion Sort runs in $O(n^{{?}^{{?}^{?}}}2)$

d$.$ Heapsort runs in $O(n^{{?}^{{?}^{?}}}2)$

e$.$ Quicksort runs in $O(N)$