Geeze, all I do is ...
Say the "5 people" are: Red, Baseball, Volleyball, Tuna, Spagetti
I start with Red - Red is not Baseball, Volleyball, Tuna or Spagetti
Next, Baseball - Baseball is not Volleyball (skip this one because, obviously, they are in the same category), not Tuna or Spagetti
Volleyball is not Tuna or Spagetti
and finally, Tuna is not Spagetti
I find this easy, but, am I missing anything? I'm not "sub" genius for nothing.