Recall that the mean (or average) of N numbers is just their sum divided by N. Given an unsorted array of size N, which of the following cannot be

Recall that the mean (or average) of N numbers is just their sum divided by N. Given an unsorted array of size N, which of the following cannot be determined in O(N) time? Mark (e) if all can be determined in O(N) time.

(a) The mean (b) The largest key in the array (c) The smallest key in the array (d) The sorted-order position of the key in the first element of the array.

(e) All of the above can be determined in O(N) time.