26. In a linked-based implementation of the ADT list with only a head reference, what is the performance of removing an entry at the end of the list? a. O(n) b. O(n) C. O(log n) d. 0(1) 27. In a linked-based implementation of the ADT list with a tail reference, what is the performance of removing an entry at the beginning of the list? a. 0(1) b. O(log n) C. O(n) d. O(n). 28. In a linked-based implementation of the ADT list with a tail reference, what is the performance of removing an entry that is not at the beginning of the list? a. O(n) b. O(n) C. O(log n) d. 0(1)