L.M.Suresh Kumar

In the given scenario, the problem has been solved and that too, by switching the lights on after dusk and not by working on any other events. So, all the events are sufficient and necessary causes except F (use of chemicals). Therefore, I prefer to hold on to Option 1 (my original choice) L M Suresh Kumar

1. A, B, C, D, and E The assumption here is that, these are the only causes that decide the action. F is not included, so we do not seal the possibility of any other innovative solution.