I had gone through the Tutorial uploaded on this website about the sorting algorithms, but I have one doubt

Which of the following sort procedures takes the lowest average time

a) Merge sort b) Heap sort c) Quick sort d) Selection sort

Here form the tutorial I came to know that average time of all three options a , b , c are same , it is O(nlogn), so what is the correct answer to this MCQ

Thanks a lot in advance