We want to compare the worst-case complexity of the sorting algorithms Insertion Sort, Merge Sort, HeapSort, and QuickSort as studied in this course. However, we want to compare their worst-case efficiencies when applied to sorting arrays with restricted element types. More specifically, suppose A[1..n) is an array of n elements, where each element is a single decimal digit 0 to 9. In this case, the worst-case most efficient sorting algorithm is O a. Insertion Sort O b. MergeSort O c. QuickSort Od. HeapSort