Consider a singly linked list that has two members: mFirst, a pointer to the first element in the list, and mLast, a pointer to the last element in the list. The time of which of the following operations depends on the length of the list?

a) Delete the last element of the list.
b) Delete the first element of the list.
c) Add an element after the last element of the list.
d) Add an element before the first element of the list.
e) Interchange the first two elements of the list.