Explanation:

Stable Sorting Algorithm:
A sorting algorithm is said to be stable if it maintains the relative order of equal elements in the sorted output as they appeared in the original input. In other words, if there are two elements with equal keys, the element that appears earlier in the input should also appear earlier in the sorted output.

Stable Sorting Algorithms:
1. Insertion Sort: It is a stable sorting algorithm. It works by repeatedly inserting an element from the unsorted part of the array into its correct position in the sorted part of the array. It maintains the relative order of equal elements.

2. Merge Sort: It is a stable sorting algorithm. It works by dividing the array into two halves, sorting each half recursively, and then merging the sorted halves. During the merging process, it compares the elements from the two halves and maintains the relative order of equal elements.

3. Quick Sort: It is not a stable sorting algorithm. It works by selecting a pivot element and partitioning the array into two sub-arrays, one with elements smaller than the pivot and the other with elements larger than the pivot. The pivot element may not retain its relative order during the partitioning process, so the algorithm is not stable.

4. Bubble Sort: It is a stable sorting algorithm. It works by repeatedly swapping adjacent elements if they are in the wrong order. It compares and swaps elements pairwise, hence maintaining the relative order of equal elements.

Conclusion:
Out of the given options, Quick Sort is not a stable sorting algorithm. Quick Sort does not guarantee the relative order of equal elements in the sorted output.