Big Oh notation-worst case

Using Big Oh notation,indicate the time requirement for each of the following tasks below in the worst case

2. Using Big Oh Notation, indicate the time requirement for each of the following tasks in the worst case scenario. a) Display all the integers in a chain of linked nodes in reverse order. b) Display the nth integers in an array of integers from end. c) Compute the sum of the first n odd integers in a chain of linked nodes. d) After arriving at a party, you shake hands with each person there. e) Each person in a room shakes hands with everyone else in the room