A sorting method is stable if equal keys remain in the same relative order in the sorted sequence as they were in the original sequence. (That is, a sort is stable if for any i < j such that initially E[i] = E[j], the sort moves E[i] to E[k] and E[j] to E[m] for some k and m such that k < m.) Which of the following algorithms are stable? For each that is not stable, give the relative order of two equal keys is changed.

1. Insertion Sort.
2. Maxsort
3. Bubble Sort
4. Quicksort.
5. Heapsort.
6. Mergesort.
7. Shellsort.
8. Radix Sort.