(1) Three passengers are waiting for an elevator in different floors of a 6-story building. The elevator must stop at the floors as follows: a) Passenger 1 is at 1st floor and he presses the elevator button as the first person. He wants to go to 3rd floor b) Passenger 2 is at 2nd floor and he presses the elevator button as the second person. He wants to go to 4th floor. c) Passenger I gets off the elevator when the elevator gets to 3rd floor. d) Passenger 3 is at 4th floor and he presses the elevator button as the third person. He wants to go to 1st floor. e) Passenger 2 gets off the elevator when the elevator gets to 4th floor. f) The elevator moves toward first floor where passenger 3 gets off the elevator. Write a C program that uses linked lists or stacks to pick up the passengers or drop them off at the desired floors. Draw the block diagram of your linked list or stack at each step. hint: In the beginning and at the end, the elevator is empty. hint: you can use either the floor number or the passenger number as the data member of your structure. hint: getting in to the elevator is equivalent to inserting a node and getting off the elevator is equivalent to removing a node