Which of the following operations has a worst-case runtime of O(1)? (mark ALL that apply) Select one or more: a. Adding to the end of a singly linked list that uses a head pointer and no tail pointer O b. Removing the last element from a doubly-linked list that uses a head pointer and a tail pointer o c. Adding to the end of a singly linked list that uses a head pointer and a tail pointer O d. Inserting a new element at index 24 of an array-based list that contains 82 elements e. Adding to the beginning/front of an array-based list that doubles in capacity on each resize Of. Inserting a new element at index 19 of a circularly linked list that contains 72 elements and uses a tail pointer (no head pointer)