Input is already in ascending order, means it is the worst-case situation. Option 1: Quicksort runs in Θ (n2) time In quick sort worst case, first or last element is selected at the pivot element. [ alt="F2 R.S Madhu 17.12.19 D1" src="//storage.googleapis.com/tb-img/production/19/12/F2_R.S_Madhu_17.12.19_D1.png" style="width: 285px; height: 275px;"> For a quicksort, in worst case recurrence relation will become T(n) = T(n-1) + T (1) + n Which gives T(n) = Θ (n2) So, it is correct. Option 2: Bubble sort runs in Θ (n2) time If array is already sorted in ascending order, then at that time there will be no swap after the completion of inner for loop of bubble sort. In this way, bubble sort will take Θ (n) time complexity. Option 3: Merge sort runs in Θ (n) time Merge sort uses the divide and conquer policy to sort the elements. As elements are already sorted in ascending order. Recurrence relation for merge sort; T(n) = 2 T (n/2) + n This will give Θ (nlogn) time complexity. Option 4: Insertion sort runs in Θ (n) time When a new element which is greater than all the elements of the array is added, then there will be no swap but only a single comparison. In n -1 swaps, only 0 swaps and n-1 comparisons are there. Total time complexity in this case will be Θ (n).