29. Which of the following statements are true?
R and QS returns the sorted list after O(n log n) comparisons on all inputs
R and QS never returns an unsorted list on any input.
For every input, there exist a random choice of pivots for which the algorithm makes O(n2) comparisons.
For every input, most of the random choices of pivots result in the algorithm making O(n log n) comparisons.