3.) Design a PLC program that will perform the following tasks: a) When switch "S1" is closed, three lights will come on. b) If switch "S2" is then closed, two of the lights will turn off, leaving one light on. c) If switch "S3" is then closed (switches S1,S2, S3 all closed at this point), one of the lights that turned off in operating state b above will come on, thus showing two lights on. d) Closing "S4" turns off any of the three lights that happen to be on. (20 Points)